Also See
RDC FAQ

Steam, Rolling Stock & Misc Info Prototype FAQ Part 1

Subject: rec.models.railroad FAQ PROTOTYPE part 2 of 2
rec.models.railroad FREQUENTLY ANSWERED QUESTIONS
PROTOTYPE QUESTIONS (PART 2 of 2)

This started out as part of the rec.models.railroad FAQ,
but now I feel that it belongs in the misc.transport.rail.*
hierarchy.

Urban_Fredriksson@icl.se

This parts contains the following subjects:


   
DIESEL LOCOMOTIVES, INTRODUCTION
   
DIESEL LOCOMOTIVES, DETAIL
   
DIESEL LOCOMOTIVE, THEORY
DIESEL LOCOMOTIVE, TRACTION
DIESEL LOCOMOTIVE, DYNAMIC BRAKES
   
DIESEL LOCOMOTIVES, NAMING
CONRAIL, F SERIES
   
ELECTRIC LOCOMOTIVES, DETAIL
   
ELECTRIC LOCOMOTIVES, THEORY
   
ELECTRIC LOCOMOTIVES, TGV
   
GAS-TURBINE LOCOMOTIVE, DETAIL

------------------------------------------------------------------------------
DIESEL ENGINES
------------------------------------------------------------------------------

CONRAIL, F SERIES
Did CONRAIL use the F-series diesel?

	Conrail had MANY F-units when it first started off. They were all
	in the 1600-, 1700- and 1800-series. The majority of these units
	were F7A's, with a handful of F3A's. Here's a breakdown for you:

	Unit   Former RR  Amount
	------ ---------- ------
	F7A    PRR        2
	F7A    NYC        96
	F7A    DL&W       5
	F7A    Erie       6
	F7A    D&RGW      2
	F3A    Erie       4
	F7B    DL&W       6
	F7B    Erie       5
	F7B    PRR        1
	F7B    NYC        7
	F7B    D&RGW      2
	F3B    Erie       4
	FP7A   PRR        18
	FP7A   Reading    3

	Notable amongst this roster are a few things:

	* The lone pair of Pennsy F7A's, the last of PRR's once major F-unit
	  freight fleet.
	* CR 1792 was the only one to receive CR blue paint - but no "wheel-
	  on-rail" logo. All it got was "CR" lettering.
	* The four Rio Grande units might have surprised some people. These
	  were picked up by PC to be used as trade-ins to EMD. But ever-chintzy
	  PC found two A units and two B units to be in decent shape, and they
	  lasted into Conrail. These units are distinguisable by their dual
	  headlights.
	* The Erie F3's - perhaps the oldest units on the CR fleet! These were
	  phase IV F3's (resembled F7's)
	* The three RDG FP7's spent their lives on SEPTA, even though they were
	  on the CR roster. They later got SEPTA paint, and today two of 'em
	  have been restored to their original Reading paint.



DIESEL LOCOMOTIVES, INTRODUCTION
Can you give me an introduction to diesel locomotives?

	Locomotive manufacturers

		EMD:    Electro-Motive Division of General Motors
	        	Before being bought by GM, it was EMC - Electro
	        	Motive Corporation. 
		GE:	General Electric
		Alco:	Americal Locomotive Works
		Baldwin:Baldwin Locomotive Works

	Baldwin Locomotive Works was named after the "founding father"
	Mathias(?) Baldwin. In 1928 the Baldwin works moved from Philadelphia
	to nearby Eddystone, Pa. For a complete story of "the works", check
	the book "The Locomotives that Baldwin Built" by Fred Westing, 1966
	by Superior Publishing Co., Seattle Washington, also re-printed by
	Bonanza Books.
	
		Lima:    Lima-Hamilton
	        BLH:     Baldwin,Lima,Hamilton
	
	Lima started out building power saws and other logging equipment.
	Ephriam Shay came to them with a patent for a crazy locomotive, and
	convinced them to build Shays.  That is what got them into the
	locomotive business.  They soon dropped the logging equipment and
	built only locomotives, conventional as well as Shays.  The General
	Equipment Co. in Hamilton, OH, built diesel engines, but not
	locomotives.  The Lima-Hamilton merger happened at the end of the
	steam era and L-H was not successful in producing diesel locos. Baldwin
	merged with L-H, but the companies involved were in poor financial
	shape, so the merger did not save them.  BLH continued for a few years
	building heavy equipment, then finally went under in the 60's.
	
		MLW:     Montreal Locomotive Works
	
	The successor to MLW was Bombardier who built some MLW designs for a
	while in Canada.  The Montreal MLW/Bombardier plant is now run (owned?)
	by GE-Canada. Bombardier still manufactures railroad passenger cars in
	Barre, VT.
	
	        FM:      Fairbanks-Morse
	
	Also note that FM and Baldwin designs were built in Canada under
	license by CLC - Canadian Locomotive Company.
	
	Only EMD and GE are still producing railroad locomotives. EMD is now known
	as GM and locomotives are now all built in Canada.   I believe
	the diesel engines (motors) are still built in the US.   
	There are also overseas licensees of GM designs / parts:
	e.g.       Clyde Engineering
	Australia
            NOHAB (now Kalmar Verkstad)                 Sweden
            Macosa
	Spain
	Others build engines under license,etc.
	I recommend an excellent website devoted to export GM locomotives -
 	http://EMDExportRailfan.net/
	also
 	http://locopage.railpage.org.au/clyde.html
	
DIESEL LOCOMOTIVES, DETAIL
How about more detail on diesels.

	Abreviations:
	EMD		Electro-Motive Division of General Motors
	GE		General Electric
	Alco		Americal Locomotive Works
	Baldwin		Baldwin Locomotive Works
	Lima		Lima-Hamilton	
	BLH		Baldwin, Lima, Hamilton
	MLW		Montreal Locomotive Works
	FM		Fairbanks-Morse
			and there were a few other small ones.	

	Only EMD and GE are still producing railroad locomotives	

	EMD's first main model was the FT which I'm sure stood for freight. It
	had 1350 hp(horse power) They were designed to be semi-permanently
	coupled and sold usually as sets. They came in both A and B. An A unit
	is one with a cab and controls, a B unit is an engine without a cab,
	or with a cab with the controls removed.

	This was followed by the following engines:	
	-------------------------------------
	UNIT			HORSEPOWER
	-------------------------------------
	F2A,F2B			1350
	F3A,F3B,F7A,F7B		1500
	F9A,F9B			1750
	-------------------------------------

	These are all cab units. (no walkways, and the outer shell is built as
	part of the frame, to give it strength)	They also had B trucks, which
	means that they had 2 axles on each truck each with a traction motor.
	(which drives the axle using electricity from the generator)	

	There was also the E unit, which is like the F unit, except it has 3
	axle trucks, called A1A since the center axle is not powered. They also
	have 2 engines in them, to give them more hp.	

	Here are the models:	
	-------------------------------------
	UNIT			HORSEPOWER
	-------------------------------------
	EA,  EB			1800
	E1A, E1B		1800
	E2A, E2B		1800
	E3A, E3B		2000
	E4A, E4B		2000
	E5A, E5B		2000
	E6A, E6B		2000
	E7A, E7B		2000
	E8A, E8B		2250 
	E9A, E9B		2400
	-------------------------------------

	These also are cab unit style.The model number on both of these changed
	usually when EMD made a change - either externally or internally.	

	Before making the F7, EMD introduced a new model type, called the BL1	
	It stood for Branch Line, had 1500 hp, and had the same motor as the
	F7 and GP7. (which I will explain later) They followed this by the BL2,
	although it is argued what the change was. This engine had most of the
	cab style, with notches along each side, that would allow the engineer
	to see behind him better.

	This was followed by the GP7, which was concurrently produced with the
	F7. The GP series stood for General Purpose, and had walkways along
	each hood. It came in passenger and freight versions. Passenger
	versions had a steam generator in the short hood (typically called
	the nose) to heat the passenger cars. This engine had B trucks and
	1500 hp	

	Here is a list of GP style engines:	
	-------------------------------------
	UNIT			HORSEPOWER
	-------------------------------------
	GP7			1500
	GP9			1750 
	GP15			1500
	GP18			1800
	GP20			2000
	GP28			1800
	GP30			2250
	GP35			2500
	GP38			2000
	GP39			2300
	GP40			3000
	GP40X			3500
	GP50			3500/3600
	GP60			3800
	-------------------------------------
		
	The EMD currently builds is the GP60.	

	The next frieght style is the SD series, which stands for Special Duty.	
	These have C trucks, instead of B trucks, and are typically a lot
	heavier	then their GP counter part.

	Here is a list of their models:	
	-------------------------------------
	UNIT			HORSEPOWER
	-------------------------------------
	SD7			1500 
	SD9			1750 
	SD18			1800 
	SD24			2400 
	SD28			1800 
	SD35			2500 
	SD38			2000 
	SD39			2300 
	SD40			3000 
	SD45			3600 
	SD45X			4200 
	SD50			3500/3600 
	SD60			3800 
	SD70			4000 
	SD75
	SD80
	SD90			6000
	-------------------------------------

	Current production models are SD60, SD70 and SD75,
	SD80 and SD90 will be coming in 1996 or 1997.
	Most of these engines were used
	for freight, but they could be purchased with steam generators(usually
	located in the short hood) for passenger service. EMD also produced	
	a couple with the steam generator in the rear. These were the following
	models:	SDP40, SDP45, GP40P and GP40TC. The GPs are a 2 axle
	configuration. Then there is the later F series, which were basically
	like the GP and SD, but had a cowling over the engine, instead of
	walkways. This cowling is not part of the structural support, unlike
	the earlier F series.	

	These engines include:	
	-------------------------------------
	UNIT			HORSEPOWER
	-------------------------------------
	F40PH			3000   -standard Amtrak engine everyone
					 knows and loves :)	
	SDP40F			3000     later rebuilt into F40s
	F45, FP45		3600	 the FP had a steam generator in it
	-------------------------------------
	We also have the SD40F,SD50F and SD60F which are SD40,SD50/SD60's 	
	with cowling over them instead of walkways. These were all bought
	by Canadian railroads's.

	Now to the switchers, another long list!	
	A switcher is typically, small, lightweight, and has a cab at one end,	
	and no nose, instead it usually has large windows for visibility. EMD
	started out with the NC which had 900 hp, and was experimental,	and
	then followed with the following models:	
	-------------------------------------
	UNIT			HORSEPOWER
	-------------------------------------
	SC,SW			600	(SC stood for cast frame,
					SW stood for welded frame)	
	NC, NC1, NC2, NW	900	(c for cast, w for welded)
	NW1, NW1A		900
	-------------------------------------
	Originally, "S" stood for 600 and "N" stood for 900, but that was
	changed later.

	-------------------------------------
	UNIT			HORSEPOWER
	-------------------------------------
	NW2			1000
	NW4			 900
	SW1			 600
	NW3,NW5			1000
	SW8			 800
	SW600			 600
	SW900			 900
	SW7			1200
	SW9,SW1200		1200
	SW1000,SW1001		1000
	SW1500, MP15		1500
	SW1504			1500
	-------------------------------------
	All EMD SW/MP series production has ended.
	The MP stands for Multi Purpose, still looks like a switcher though.
 	The other odd model EMD
	produced was the DD series, which had DD trucks	(4 axles, 4 traction
	motors per truck) These were double ended diesels, and were roughly
	like 2 engines put together in one.

	They had the following:
	----------------------------------------------
	UNIT           HORSEPOWER
	----------------------------------------------
	DD35              5000
	DDA35X         5000
	DDA40X         6600
	------------------------------------------
	There were 30 of the DD35 built.  Three went to the SP and 27 to UP.
	The DD35 was a cabless booster unit.     Only 15 DDA35X ( with cab) were
	built and all of them went to UP.  There were 47  DDA40X (with cab)
	built and all went to UP.
	
	GE's roster is a bit easier to describe. They started with the U
	series, which stood for Universal. They are either B or C, depending
	on whether they	had B trucks or C trucks. The U series had the
	following models:	
	-------------------------------------
	UNIT			HORSEPOWER
	-------------------------------------
	U18B			1800
	U23B,U23C		2250
	U25B,U25C		2500
	U28B,U28C		2800
	U30B,U30C		3000
	U33B,U33C		3300
	U36B,U36C		3600
	-------------------------------------
	There was also a U50 and U50C which was a double U25, with either
	2 sets of B trucks on a span bolster (U50) or on C trucks (U50C).

	All GE models use their hp in hundreds as part of the model
	designation along with the type of trucks and the engine series.	

	Sometime in the late 70's (1977 I think) they dropped the U series, and	
	went to the -7 series. All further models looked like this:	
	-------------------------------------
	UNIT			HORSEPOWER
	-------------------------------------
	B23-7, C23-7		2300
	B30-7, C30-7		3000
	B36-7, C36-7		3600
	-------------------------------------
	I don't believe they carried the C232 or U33 into the -7 line. In the
	mid 80's, (around 1984) they dropped the -7 line and went to the -8
	line, which is the current production line. These are the following
	models:
	-------------------------------------
	UNIT			HORSEPOWER
	-------------------------------------
	B32-8, C32-8		3200
	B36-8, C36-8		3600
	B39-8, C39-8		3900
	B40-8, C40-8		4000
	-------------------------------------
	The C44-9W, C40-9, AC4400CW and AC6000CW are the
	current production models.
 	They have also
	flipped the designation to DASH-8 40B and DASH-8 40C, although many
	railroads retain the older designation.

	There is also a modification on the current production of engines, that
	being a cowl (like described before) or a safety cab. For EMD's, the
	wide nose is designated by adding an M after the model name (like SD60M
	or GP60M) on GE is is a W, (Like CW40-8,DASH-8 40BW). They also have
	the full width cowl with a W (DASH 8-40CW) bought only by Canadian
	National and BC Rail (British Columbia Railway).

	Most of this information is in the "Second Diesel Spotters Guide" or
	"Diesel Spotters Update".  I won't go into the other RR's, since I'm
	not rewriting their books, but this gives you a general description of
	the two most prominent locomotive makers. GE currently is producing
	more than EMD, EMD had been on top since the beginning. (of
	mass-produced diesel locomotives)

Note:  One of the early GE diesels engines was initially designed and 
          manufactured by a company called "Cooper-Bessemer". They sold the 
          first one to GE in the 1930's (When they still required the engine manufacturer
          to produce the entire locomotive). Eventually one-half of our "FW" engine 
          line was being bought by GE (1945 and later) with GE finally purchasing the 
          complete rights to the engine line somewhere in the 50's.
          Per Bill Johnson bjjohns@cooper-energy-services.com

DIESEL LOCOMOTIVE, THEORY
How does a diesel locomotive work?

	Actually, this is a trick question.  Locomotives come in:
		diesel-mechanic,
		diesel-electric, and
		diesel-hydraulic.

	The diesel engines are huge internal combustion engines (sometimes
	more than one per locomotive), named after Rudolf Diesel who patented
	the concept in 1892.  In a diesel-electric they are used to power
	electric generators, and the electricity is used to drive electric
	motors.  These are called traction motors and one is attached by a
	gear system to each powered axle.

	Diesel-mechanic locomotives are those that work just like a diesel
	car or lorry, they have a motor, gear box, etc.  Their power is
	limited because the mechanical parts cannot stand even a thousand hp.
	
	Diesel-hydraulic are those which use a hydraulic gear box. The
	principle can be illustrated this way: imagine a lake and put there
	a mill at the margin, now imagine a big fan driven by the motor that
	makes the water in the lake go round in circles. The result is that
	the wheel off the mill starts turning also. This is roughly how
	hydraulic transmission works. [or you can think of an automobile's
	automatic transmission...]

	It turns out to be very difficult to build these to handle the large
	loads involved, so all modern locomotives [in the United States - see
	below] are of the diesel-electric variety.
	
	Until 1980, there were still modern diesel-hydraulic locomotives built
	for the Die Bahn in West Germany (three major series: the
	good old two- motored 220/221 (V200), the light 211/212 with one motor
	and the cab in the middle and the 215/216/217/218/219 with one
	motor/two cabs for mixed service).  
	Class 236            C switcher
	Class 260 / 261    C switcher
	former DR Class 106 / 105 switcher
	former DR Class 110 / 112
	former DR Class 118 / 119
	former DR Class 120 (Russian designed and built)
	former DR Class 130 / 131 / 132 / 142 (Russian designed and
	built - some now repowered with Catapillar engines)
	Class 210 (similar to Classes 215 / 216 / 217 / 218 / 219)
	Class 213 (version of Class 211 / 212)
	Class 290 / 291

	Today many diesel locomotives are built for the smaller private 
	railways and for export, including some powered by GM motors. 
	New diesel locomotives will be built in the diesel electric
	technology with 3-phased AC transmission.
	
	Another hybrid was the 2-and 3-power diesel-electric. GE built 44 of these 
	boxcabs where the diesel engine ran at constant speed, charging storage 
	batteries from which traction current could also be drawn. 	The 3-power unit 
	had a single pantograph and a 3rd rail shoe, while the 2-power units lacked the
	3rd rail. EMD GM built 60 FL9 s for New Haven (now rebuilt many times and 
	serving AMTRAK and others). It is an FP9 with B-A1A running gear.   
	The A1A truck carries the 3rd rail show for electric current collection, 
	but retains the 567C/ D1 1750 / 1800hp motor.  

	Finally we have the steam-electric.  I don't have the references in
	front of me, but I believe the New York Central experimented with an
	engine which looked like an F3 but which had a coal-powered steam
	boiler which as used to run a generator, with the rest of the system
	as in a diesel-electric.  This is even more speculative than the
	diesel-hydraulic description, so don't bet any money on it.

	In the UK there have been 2 electro-diesel types.    10 Class 74s were
	 built by converting straight electrics of the Class 71. They were 
	fitted with Paxman 650hp diesels providing power to the generator.
	Under 3rd rail electric traction they produced 2300hp at the rail (2550hp).
	The Paxman motors were troublesom and the Class 74 was withdrawn in 1977.  
	Converted 1967. The other type is much more successful. The Class 73 
	(49 built) have an English Electric 4SRKT 4-cylcinder motor producing 
	600hp - very reliable.  Under 3rd rail electric traction they produce 1600hp
	(nominal),  1420hp at rail and 2450hp at 37mph.   Most are still in
	service.   Neither the Class 73 or 74 have or had pantographs.   The
	Class 71 straight electrics had one central pantograph for use in
	sidings were the 3rd rail was replaced by a trolly wire source of
	current.   The pantograph was removed during the conversion to Class 74.

	
LOCOMOTIVE TRACTION

What creates "adhesion" characteristics?

Per James Robinson:
Adhesion is a measure of how effectively a locomotive can translate its
weight into pulling power before the wheels spin out of control.  Many
things can influence this including the weather conditions, the profile
of the wheel tread and the rail head, contamination on the rails, the
mechanical design of the trucks, and the electrical control system.  The
electrical system is where the greatest improvements have been
accomplished.

In steam engines and early locomotives there wasn't any type of
automatic wheel slip control system.  It was up to the engineer to cut
the power on the locomotive whenever the wheels started to slip.  On
these early diesel engines, most railroads felt that about 12 or 14
percent adhesion was the best you could expect for day to day
operations.  Steam engines could deliver more since the side rods tied
the axles together, and one wheelset couldn't slip by itself with this
arrangement.

The next development was the installation of a light on the control
stand that indicated that wheels were slipping.  This was accomplished
by measuring the voltage or current imbalances between motors and
lighting a light on the control stand whenever the imbalances exceeded a
certain amount. (Simply stated, the voltage of a motor varies with its
rotational speed, so if one motor is spinning faster than another, there
will be a difference in voltage between them.) This didn't improve the
dispatchable adhesion in itself, but permitted multiple unit control
since the slip signal was wired between locomotives, and the engineer
therefore didn't have to be sitting on the slipping locomotive to know
there was a problem.

Some bright designer then decided to use the slip signal to
automatically vary the power of the locomotive:  Whenever the system
detected a slip, the power of the locomotive would be automatically cut
to stop the slip, then carefully reapplied.  The engineer still had to
modulate to throttle to keep the system from working too hard, but since
the automatic system could react more quickly than the engineer could,
the railroads increased the dispatch adhesion to about 16 or 18
percent.  Refinements in the system eventually permitted dispatch
adhesions of 18 to 20 percent.

At this point the electrical control systems graduated from slip control
to adhesion control.  This is because newer control systems were
designed that actually allow the wheels to slip slightly, on purpose. 
It is called creep control.  On a heavy pull the wheels will typically
by turning a couple of miles an hour faster than the locomotive is
moving, and thereby gain the greatest pulling power from the
locomotive.  You can sometimes hear the effect on a heavy pull when the
wheels begin to sing.  This means the control system is working hard. 
The theory is that the slipping wheels will burn off any contamination
between the wheels and the rail and thus give a better grip on the
rails.  With this type of system installed on DC locomotives the
adhesion ratings jumped to 25 or 28 percent dispatch adhesion.

Finally, AC traction technology permitted even finer control of wheel
creep.  These types of locomotives typically are rated at between 31 and
34 percent dispatch adhesion.

> Also, if AC motors do not have brushes, how does current get to the
> internal rotating part?  (I assume all electric motors have two
> electro-magnets--a stationary part on the outside and a rotating part on
> the inside).

On AC motors of the type used on locomotives, the magnetic field on the
outside is in fact not stationary.  While the mechanical parts are, the
electric field and therefore the magnetic field are actually rotating 
around the rotor at a rate proportional to the frequency of the
electricity.  This induces voltage in the closed loops of wire in the
rotor without any electrical connections being necessary.
  
In a way, it's similar to how a transformer works:  There are no
physical connections between the primary and secondary windings of a
transformer, but the changing electical field of the primary will induce
a voltage in the secondary windings.
 If the adhesion control system is not designed properly, high wheel slip
speeds will not only do damage to the wheels, but to the rails as well. 
The horsepower of a wildly slipping wheel put into the wheel / rail
contact patch will generate very high heat.  

North American railroads are operating their locomotives with dispatch
adhesion levels in the range of 0.3-0.35 on a daily basis.  Trains will
continuously operate at these levels of adhesion for up to an hour or
two while pulling up the ruling grades.  Occasionally, trains will
operate over tonnage, and on a good day will still make it over the
hills with in excess of 0.35 adhesion.  Wheel life has not significantly
reduced since the introduction of these locomotives.  Certainly the
shear strength of the steel will become a limiting factor at about the
0.4 level.


Wheels on locomotives without individual control have to be closely
matched for optimum performance.  In the case of EMD AC locomotives, the
wheels have to be matched within each truck, since all axles in each
truck are powered by a separate inverter.  Railroads seem to be able to
handle this requirement OK.  In any event, if there is a mismatch, the
larger wheel will tend to be ground down over time to match the rest of
them.

> This debate 
> has been solved some years ago already. For maximum
> adhesion, you need individual control of the axles. But the difference
> isn't huge, and often it does not justify the higher price. For
> 'difficult' operation conditions (wet/cold climate, steep grades, heavy
> trains), individual axle control is definitely preferable though.

There is probably not that great a practical difference between the two
strategies.  Most railroads are dispatching their EMD and GE AC
locomotives at pretty well the same adhesion levels.  Further, GE and
EMD seem to both be able to sell their locomotives at about the same
price, so railroads are not voting for one system over the other with
their purchase dollars.


So Why Induction Motors:
        They are lovely things, mechanically simple & cheap (roughly 30%
        cheaper (and lighter) than an equivalent DC Series Comutator motor,
        which is what lives under the 'DC' loks.  Also the induction motors
        are more reliable, and smaller.  Did i mention lighter?  And suitable
        for higher voltages?

SO why NOT induction motors, until about 10 years back?
        DC series comutator motors could be more efficiently controlled
        with the technology available.  An AC Induction motor needs power
        semiconductors (in the 1000v/1000A range) AND effectively needs
        'puters to control them.  Until uprocessors and modern power
        semiconductors 'enabled' them, AC Induction (and synchronous) motors,
        tho nice were a pain to use.  (there wre previous rail applications,
        but very specilized.)

        Controlling (efficently) the speed/torque of an AC induction motor,
        of high power (1000 hp per motor....) means generating three phase
        power of controlled voltage AND controlled, adjustable freuqency.
        power of controlled voltage AND controlled, adjustable freuqency.
        roughly, up to 100 off Hz, from '1' Hz.
	
DYNAMIC BRAKES

How is dynamic braking  accomplished on an AC unit?

Per James Robinson:
Getting the AC system to work in dynamic braking is not easy.  However,
the end result is a very good DB system since it is functional down to
practically a standstill without fading. Dynamic brake on locomotives
with DC motors will peak at about 20 or 25 mph and fade to nothing as
the locomotive slows to a stop.  Extended range will provide a higher
force, but only down to about 7 mph, where it will begin to fade.  There
is also a brake called double extended range, which gives effective
brake down to even lower speeds before fading, but very few have been
sold. Further, DB on an AC locomotive is more resistant to sliding wheels than
an equivalent DC based system.

Back to how the system works on AC units.  First, to get the locomotive
to pull, the electrical field in the stator rotates slightly faster than
the rotor itself is turning.  The peak torque is typically achieved when
the field is rotating about five percent faster than the rotor is
turning.  To get dynamic braking, the reverse also holds true:  If the
field is rotating slower than the rotor is turning, then there will be a
tendency to slow the rotor down, which is dynamic braking.  The tricky
part, which is handled by the electronics, is that the system has to
draw power off of the motors and apply it to the dynamic brake grids to
dissipate the energy being generated.

DIESEL LOCOMOTIVES, NAMING
How are diesel locomotives identified?

	North American diesel locomotives are designated by the number of
	powered axles, divided into trucks.  The letters A,B,C,D stand for
	1 through 4 axles, so an EMD FT (see below) with 2 trucks each of
	which contains two driving axles is a B-B. Early locomotives were
	made with A1A trucks. (2 axles, the center one unpowered)
	
	A units have a cab with controls for the engineer. B units are
	basically A units with no controls. Slugs are a cut-down frame filled
	with concrete. They have only traction motors, and receive power from
	an attached engine.
	
	A slightly different convention is used in Europe, possibly due to the
	wider range of designs employed. The european version is as follows:
	
	The number of non-driven axles is determined by an arabic number:
	1 = 1 axle, 2 = 2 axles in one frame, and so on.
	
	The number of driven axles is determined by an uppercase letter:
	A = 1 driven axle, B = 2 driven axles in one frame, and so on.
	
	A small 0 (or o) after an uppercase letter means that each axle
	is driven by its own motor.
	
	Parentheses () around letters and numbers indicate they are built into
	one frame or bogie. 
	
	An apostrophe (') after a number, a letter or a parenthesed expression
	means that these axle(s) are situated in a bogie, independent from the
	frame.
	
	Independent vehicles are separated by a plus (+) sign.
	If you see something like 2'2'2'2'2'2'.... this is probably an
	articulated train.
	
	Examples:
	2'C2' = a bogie of two axles, three driven axles in the frame, and
	  another bogie of two axles
	Bo'Bo' = two bogies, each with two axles, each axle driven by its
	  own motor
	(1'C)'(C'1)' = two bogies, each with three axles driven by one
	  motor and one independent axle
	
	In Britain, the convention is slightly different again. The brackets and
	apostrophes are not used. A normal locomotive with two independent
	two-axled bogies will be a Bo-Bo. However a few older classes, notably
	class EM1 (later class 76), have (or rather had) a link between the
	bogies to avoid transmitting the entire tractive effort through the
	bogie/body joint. These locomotives are referred to as Bo+Bo.
	
-------------------------------------------------------------------------------
ELECTRIC ENGINES
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ELECTRIC LOCOMOTIVES, DETAIL
What are the most important electric locomotives?

	SBB CFF FFS (Switzerland):
	 Ce 6/8 II;  (1'C)'(C1')'; 1.65 MW;  65 km/h
	 Be 6/8 III; (1'C)'(C1')'; 2.575 MW; 75 km/h
	  The `Crocodile', maybe the most famous electric locomotive ever. It
	  was built since 1919 for transporting heavy trains over the Gotthard.
	  This articulated locomotive was used until 1970.
	  Models of the Ce 6/8 II: Maerklin 1; Roco H0; Arnold N.
	  Models of the Be 6/8 III: Maerklin H0; Maerklin Z.
	 Re 6/6 620; Bo'Bo'Bo'; 7.8 MW; 140 km/h
	  This is still the most powerful locomotive (with one frame) of the
	  world. It was built since 1972 for all trains on mountain lines.
	  Models: Hag H0; Lima H0; Hobbytrain N.
	 Re 4/4 460; Bo'Bo'; 6.1 MW; 230 km/h
	  The `Locomotive 2000' in the newest technology, designed by Pinin-
	  farina, built since 1991. Variants of the 460 will be built for the
	  BLS (Switzerland) and for the VR (Finland).
	  Models: Hag H0; Maerklin H0; Roco H0.
	
	DB DR (Germany):
	 Class 118 (E18); 1'Do1'; 3.04 MW; 150 km/h
	  From 1935 to 1955 these locomotives were built for fast passenger
	  trains. They were used until 1980, in Austria (OeBB 1018) until 1990.
	  Models: Maerklin H0 (DB 118), Roco H0 (DB 118, OeBB 1018).
	 Class 103; Co'Co'; 7.78 MW; 200 km/h
	  Since 1970, this powerful engine is used for all the fast InterCity
	  trains in Germany.
	  Models: Fleischmann H0, Maerklin H0, Roco H0; Fleischmann N, Trix N;
	  Maerklin Z.
	 Class 120; Bo'Bo'; 5.4 MW; 200 km/h
	  The prototypes of this universal locomotive with asynchronous three
	  phase motors were built in 1979; since 1987 more 120s are in regular
	  service for InterCity and freight trains.
	  Models: Fleischmann H0, Maerklin H0; Fleischmann N; Maerklin Z.
	
	SNCF (France):
	 CC 7100; Co'Co'; 160 km/h
	  In 1955 one of these locomotives established a new world record with
	  331 km/h. They were used for heavy passenger and freight trains.
	  Models: Rivarossi H0; Roco N.
	 BB 26000; Bo'Bo'; 200 km/h
	  The SYBIC locomotive, with synchronous three phase motors, is built
	  since 1990. It is used for all sorts of trains in the whole country.
	  Model: Maerklin H0.
	
	SJ (Sweden):
	 Rc1, Rc2, Rc3, Rc4, Rc5; Bo'Bo'; 160 km/h
	  The Rc series by ABB, based on thyristor technology, was built since
	  1967. Variants of the Rc are used in Austria (OeBB 1043), Norway (NSB
	  El 16) and USA (Amtrak AEM7).
	  Models: Maerklin H0 (SJ Rc2, OeBB 1043), Roco H0 (SJ Rc5; NSB El 16)
	
ELECTRIC LOCOMOTIVES, THEORY
How do electric locomotives work?

	Electric locomotives receive power at anywhere from about 500 to 25,000
	volts. At up to about 1,500 volts, a third rail is typically used. At 
	higher voltages, more separation is needed around the conductor for
	safety, but the current is reduced and so the conductor can be lighter,
	and hence the overhead wire is preferred. Power from overhead wires is
	conducted to the locomotive via a pantograph.
	
	In general, lower voltage locomotives use direct current, while higher
	voltage ones use alternating current, but this is by no means the rule.
	
	Traditional electric engines work in one of two fashions: either the
	motors are directly supplied with full voltage or the current is
	transformed to lower voltage by a transformer in the locomotive, then
	it may be directly transmitted to the motors or rectified if DC motors
	are used.
	
	The earliest electric locomotives had one or two large motors in the
	middle of the frame, which drove the wheels mechanically, similarly to
	the transmission of steam engines.  Since 1940 or so, each axle has
	its own motor; usually a modern locomotive has two or three bogies
	with two or three axles each.
	
	AC locomotives transform the current to lower voltage with a
	transformer, control is provided by transformer taps, or in some
	modern designs, by choppers.  Many modern AC Locomotives use DC
	traction motors, others use asynchronous (induction) motors.

	The newest engines have a DC circuit which is either fed by the DC
	from the overhead cable or by the transformed and rectified AC.  The
	electricity from this circuit is then converted electronically into
	three phase current of variable frequency and voltage, by which the
	motors, which can be built very simple, are fed.  This new technology
	allows the engines to feed the electrical energy back into the
	overhead cable while braking.

	DC locomotives traditionally controlled the current and voltage by
	changing the motor connections, from series to parallel and by adding
	resistors during starting.  Recent designs use solid state "choppers"
	to control the current, some use AC (induction/asynchronous) motors,
	even if the supply is DC. 

	Most of the fast trains of the world have electric traction.  It is
	expensive to build transformers and overhead cables above the railway
	lines, but the engines are much more powerful and less heavy than
	Diesel engines because they don't have to carry their fuel around. For
	example, a modern four axle engine (80 t) can easily have a power of
	more than 6 MW.  The electric engines don't need a mechanical
	transmission because the motors can develop high power at all speeds.
	This is particularly true for the new three-phase current technology.
	Electric locomotives are "clean": they don't pollute the local
	environment, although the power plants may depending on how they
	generate the electricity.
	
	Electrical transmission from the power source is best done at high
	voltage since this reduces losses due to resistance and can be
	accomplished with lighter cables (since the current is reduced).
	Alternating current is the preferred method since AC can be easily
	converted to DC and AC will travel further along a cable before it
	needs to be transformed.
	
	There are a wide variety of current systems, including:
	1. AC 25000 V, 50 Hz: Portugal, north France, Great Britain,
	   Denmark, Finland, Italy (in the future), south-east Europe,
	   CIS
	2. AC 15000 V, 16.66 Hz: Norway, Sweden, Germany, Switzerland,
	   Austria
	3. AC 11000 V, 25 or 60 Hz: USA (Amtrak north-east Corridor)
	4. DC 3000 V: Spain, Belgium, Italy, Poland, CIS
	5. DC 1500 V: south France, Netherlands
	6. DC 650/750/1200 V, third rail: south England, urban railways
	7. 25kV AC 50Hz was used in the London area of the former Great Eastern
	   and Tilbury lines, where overhead clearances were too small to
	   install 25kV wires. It's recently been converted to 25kV.
	
	France also has engines equiped for 25KV AC and 1500V DC in areas where
	the route takes it over track supplied by either voltage, such as the
	Marseille to Italy run.

	50kV AC 50Hz is used on the Sishen-Saldanha (?sp) iron ore railway in
	South Africa, which runs across the Namib desert and where there must
	hence be unusually long intervals between substations. [Actually it may
	be in Namibia now - I don't know where it runs in relation to the
	border]
	
	1200V DC is now sadly demised in Britain :-(
	
	The european railway companies have several types of locomotives that
	are compatible to two or more of these systems.  For example in
	France, all the TGVs (Train a Grande Vitessse = high speed train) have
	two or three systems.  There are plans to reduce the number of
	electric systems in Europe, but this seems to become very expensive.
	
ELECTRIC LOCOMOTIVES, TGV
What can anybody tell me about the TGV?

	The TGV (Train a grande vitesse) is an electric, high speed train of
	the SNCF (Societe nationale des chemins de fer francais). It consists 
	of two locomotives (each with only one cab) and an articulated 
	passenger train between them.

	The TGV holds the world speed record:
	In 1981, a TGV Sud-Est reached 380.4 km/h (236.4 mph).
	In 1988 the German InterCity Experimental reached 406.9 km/h (252.8 mph)
	but two years later the French got their record back, with a TGV
	Atlantique at 515.3 km/h (320.2 mph).

	The TGVs circulate on two high speed lines: Paris--Lyon and
	Paris--Le Mans/Tours. New lines will be built to the North
	(Paris--Sangatte/Lille/Bruxelles) and to the East (Paris--
	Baudrecourt). The existing high speed lines are going to be extended
	to Bruxelles and Marseille.
	
	The TGV roster includes:
	0. TGV 001
		1 experimental train, built in 1972, with gas turbines. 
		Today out of service.
	
	1. TGV sud-est (TGV SE)
		108 trains, each with 2 locomotives and 8 passenger sections,
		in service since 1981 between Paris and the south-east of
		France. The end bogies of the passenger consist are also
		motorized. These trains are painted orange, with a black
		window area and white stripes.

		Since 1990, they are equipped with pneumatic suspension and
		more comfortable seats. The interior seating is arranged in
		rows (open plan area only).

		Two trainsets can be coupled together. The pantographs for DC
		are those mounted in `front' of each locomotive, the standard
		type Faiveley AM is used, in the DC system both of them are
		raised. The pantographs for AC are a new, complicated two-level
		development. For AC operation, only one of them is raised,
		usually the one on the second locomotive, or at double
		trainsets on the first and last loco (to keep the maximum
		distance between them).

		Capacity: 368 seats. Speed: 270 km/h. Length: 200.1 m.
		Weight: 418 tonnes. Power: 6.95 MW.

		There are several versions of the TGV SE:
		1a. TGV premiere, first class only, for business traffic.
		1b. TGV SE (standard version): 3 first class sections,
		    bar with second class seats, 4 second class sections.
		    Models: Jouef H0, Lima H0 and N.
		1c. TGV tricourant: in addition to 25 kV/50 Hz and 1.5 kV DC,
		    this train is adapted to 15 kV/16 2/3 Hz for going to Bern,
		    Lausanne and Geneve in Switzerland.
		1d. TGV postal: mail trains, painted yellow.
		    Model: Lima H0.
	
	2. TGV atlantique (TGV A)
		105 trains, each with 2 locomotives and 10 passenger sections.
		The first TGV equipped with the more powerful synchronous motors
		They have been in service between Paris and the west of France
		since 1989.

		The TGV-A trains are painted silver, with a blue window area.
		The doors are marked with colors: ocean blue-green for 2nd
		class, cherry red for 1st class and bright yellow for the bar.
		There are 3 first class sections, one bar and six 2nd class
		sections. There are open plan areas (with the seats arranged
		in rows), but also face-to-face groups (Club duo and Club
		quatre in 1st class, Carre in 2nd class).

		There are rooms for travelling groups (Salon in 1st class,
		Kiosque in 2nd class) at both ends of the passenger consists.

		Two trainsets can be coupled together. The pantographs are the
		new type GPU, only one of them is used per trainset.

		Capacity: 485 seats. Speed: 300 km/h. Length: 237.6 m.
		Weight: 444 tonnes. Power: 8.8 MW.
		Models: Jouef H0, Lima H0.
	
	3. AVE (Alta velocidad en Espana)
		24 trains (2 locos, 8 passenger sections) were built in 1992
		for high speed lines in Spain. These trains are painted beige. 

		Capacity: 329 seats. Speed: 240 km/h. Length: 200.1 m.
		Power: 8.8 MW.
		Model: Jouef H0.
	
	4. TGV reseau (TGV R)
		A version of the TGV A with only 8 passenger section and 377
		seats. 80 trains will be built 1993/94. These trains will be
		used at the Nord line, with connections to Brussels, and all
		the other lines.
	
	5. Eurostar (ex Transmanche Supertrain = TMST)
		This is a train for the connection between London and Paris or 
		Brussels.

		The trainsets are painted in light grey, sun yellow
		and dark blue. Their unusual shape is influenced by the small 
		loading gauge in Britain.

		Unlike the TGV, the Eurostar has no electric cable on the roof,
		so both pantographs need to be raised. The trains are compatible
		with four electrical systems, including side rail DC as used in
		southern England (each locomotive has eight retractable contact 
		shoes). 38 trains are built: 31 trains with 18 passenger
		sections + locomotives, 7 trains with 14 passenger sections + 
		locomotives.
		Capacity: 710 seats. Speed: 300 km/h. Length: 393.7 m. 
		weight: 752.4 tonnes. Power: 12.2 MW.
		Model: Jouef H0 (announced)
	
	6. TGV deux niveaux (TGV 2N)
		To transport even more passengers in peak times, these trains
		have two floors. The entrances lead to the lower floor, the 
		connections between the sections are only between the top
		floors.

		The pantographs are the new computer-controlled pneumatic
		type CX ones. 

		These trains will have 547 seats in 8 passenger sections, 45
		trains are ordered for 1996.
	
	7. TGV Paris-Bruxelles-K"oln/Amsterdam
		This is a version of the TGV R for all 4 electric systems. 36
		trains are ordered by DB, NS, SNCB and SNCF.
	
	8. TGV Texas
		It is said that The TGV will be exported to Texas as well, but
		I have no further information about this.

--------------------------------------------------------------------------------
Gas Turbine Engines
--------------------------------------------------------------------------------

GAS-TURBINE LOCOMOTIVE, DETAIL
What is a "gas-turbine" locomotive?

	General Electric produced several species of gas-turbines, as did
	Baldwin.  Thye use a turbine engine and a variable vatio fluid transmission.
They are direct drive, with drive axles connecting the transmission to the
drive axles.
 The only successful
	production models came from GE, all of which were sold to the Union
	Pacific.  These came in essentially two types:
	
		- The first version was a 4,500 h.p. model introduced in 1949.
		  The prime mover was a GE gas-turbine which turned a
		  generator to provide current to eight traction motors.
		  Wheel arrangement was B-B + B-B, the same as the later U50.
	
		- The second model went into production in 1958.  
		  It consisted of two car bodies, a lead control unit and a
		  second unit containing a 10,500 h.p. GE gas-turbine.  Each
		  car body had two C trucks. At first, the two generators
		  attached to the turbine were rated together at 8,500 h.p.,
		  later uprated to 10,000 h.p. 
	
	Thirty large turbines were produced by GE.  Compared to first
	generation diesels, these machines were reliable. They consumed huge
	amounts of "Bunker C," a thick black oil which was considered waste at
	the time and was initially very cheap.  Heated tenders [to keep the
	fuel from solidifying] were provided for each locomotive, custom made
	from old steam tenders.  Bunker C became more expensive when it became
	an ingredient for making plastics.  Increased fuel expense doomed the
	gas-turbine, which could not operate with the fuel efficiency of the
	diesel. [No way was ever found to cool the turbine blades like a
	piston engine cooling system so the turbine had to operate at a lower
	less efficient temperature than a diesel.] 
	
	Gas-turbines were in revenue service roughly from 1950 to 1969.  None
	of the first generation turbines remain.  At least one of the second
	generation turbines is on display (in Ogden, Utah).
	
	Gas-turbines have also been used in Europe. The SNCF (French National
	Railway Society) introduced its Turbotrains ETG (Element a Turbine a
	Gaz) and RTG (Rame a Turbine a Gaz), very noisy passenger units of
	four to five wagons, in the sixties. They can reach 180 km/h and are
	still in use as fast trains on the non-electrificated lines today.
	
	The Canadian turbine train is the United Aircraft Turbotrain. This was
	operated by CN, then VIA, in the 1970s, but was retired between 1979 and
	1983.  There are no more Turbos in Canada. (Amtrak also tested a version
	of this train between Boston and New York).
	
	The other European companies have stopped their tests with gas turbine
	traction, because gas turbines consume large amounts of fuel and produce
	a very loud high frequency noise.