Trains. Why do trains have 3 engines at the front. 2 engines face one way and 1 engine faces the opposite?

Answer 1

Freight locomotives in North America are diesel-electric, meaning that they have a big diesel engine that drives a generator, which drives the motors that turn the wheels. They work equally well running in either direction, although obviously you want the front (lead) locomotive facing forward since the cab is at the front. The number of locomotives on a train is based on the required power--how heavy the train is and what kind of grades exist on the track. In flat areas it's not unusual to see a single engine, although it's more common to see two, since it's standard practice to keep them "lashed up" in pairs, so that it can be easily run in either direction to avoid the hassle of having to turn them around. In hill or mountain areas or with really long trains, you can see 3, 4 or more. Again in the 3-engine lash-up it would make sense to have the first and third engines pointing opposite directions so that you could run the combination in either direction without having to turn it around. On some western lines you may even see "distributed power" configurations where there are extra engines at the end or even in the middle of a train.

Answer 2

the train could have 3 engines for several reasons - the first which is probably most likely is that they had an engine die on them and probably got another one from a nearby yard or a yard no the way to whereever they were headed - another option is that they could have been picking up some engines that were repaired or serviced and were returning them to their yard - or it could be like a lot of the other folks said which was they were being used for extra pulling power or stopping power -- u got some good answers but from what my experience has been the direction an engine is facing really doesn't matter - hoghead gave u an excellent way of telling where the front of an engine is - the only problem is being able to recognize the letter thru all the dirt on the engine - a train can be pulled from either end of an engine - the seats in the cabs usually swivel allowing the engineer and conductor to face the direction their moving at all times -- just so u know, if u are able to glimpse the side of an engine and the "F" is not up front, its probably a local switcher b/c most road freights are like u described - back to back but not always, again hoghead was right when he said the configuration can vary., but usually you only see 2 engines on almost all trains now-a-days b/c of the "big power" they have now with the all electric GE's, these engines put out 6000 plus hp

Answer 3

Some very good answers above.

It's true that when most MU (multiple unit) consists are MUed, the locomotives on opposite ends face in opposite directions so that when the consist is used to run in either direction it doesn't have to be turned. But not always.

Visibility of course is the issue in most cases. But, the only standard equipment on locomotives is the frame. All else, including prime mover, trucks, wheels, etc. are all added to the customer's engine by order. That is why some engines (NS was using them for a while) are oriented with the engineers control stand on the side that will result in having the locomotive operated with the long hood forward. Not as good visibility, but much more safety for the crew when they plow into a truck or some other idiot that has put them self in the wrong place at the wrong time.

If you look closely at a locomotive, you will see the letter "F" on the side of the engine, below the catwalk, on one end or the other. This is to identify which end is the front, since you can't be sure by judging on the basis of the location of the cab, as in the case explained above. It is important for ground personnel (conductor, brakeman, swichman, hostler, etc.) to know which end is the front, because at night, when using lantern signals to control movement, the signals are given according to direction, i.e., forward and reverse. This is different from daytime hand signals, where commands are "come toward me" or "move away from me". When using radio, direction again becomes critical as the oral insturctions may be "take 'em ahead" or "bring 'em back".

There were other engines that had an engineer's control stand on both sides of the cab, called "dual control", so the engineer is properly oriented (right hand side in direction of movement) running forward or reverse. These were most common on locals and road switchers needing only one unit, and where there would be no turning facilities when the local was ready to head back to town. These were most often found on GP-9s.

But, there are no general restrictions in this area for direction of trailing locomotives so you'll see them in all kinds of different configurations.

Good question. Thanks for asking.

Answer 4

the front engine (primary engine) is the only engine that needs to face forward for the engineers to see forward, the others are simply "slaved" like drives in your PC...

Engines do not have a bias of direction when considering the mechanical, its only the operational "the engineers need to see the school bus at the crossing"-

the engines have large diesel motors that power generators giving high amp current to electric motors usually six dc motors (CoCO) per large engines, and four for yard switchers (BoBo)

with onboard computers that can very voltage, frequency, and load the Electrical drive trains are supperoir for these reasons

greater traction control, induction breaks, reverse without mechanics, less moving parts that are torqued... so reversing the engine is as simple as throwing a switch

Answer 5

Depends on the number of cars it has to pull! Full train is 110 cars generally with five engines. They usually face one ot two in the opposite direction to help at sidings changing from forward to backwards. However, the engine has forward and reverse!

Answer 6

Usually for the visibility factor if they have to go to the opposite end of the train. But sometimes it is for the FRA requirements for speed for non-lead qualified locomotives. For example, all engines that are "lead qualified" have what we call "ditch" lights on the front of the motor... these are the 2 horizontal lights just above the walkway on the front (or rear) of motors. Not all motors have these on the "long" hood end. If an engine is operating long hood forward, they are restricted to 20 MPH for all at-grade crossings (where roads cross the tracks) if they do not have ditch lights on the forward end of the lead locomotive.

Putting engines long hood to long hood, or in your scenario (2 forward, and one backwards) this allows ditch lights to be on the front, and allowing a locomotive to operate at maximum authorized speed on the section of track that it is running on.

Answer 7

because when in the yard of final destination and the train is being re assembled different engines are to be used as going the other direction or needed for higher tonnage and when this happens there is less turntable usage and the lead locomotive will be facing with the engineer sitting on the right side of the track for greater vision.

Answer 8

Locomotives running together can be facing opposite directions for any number of reasons. However, the vast majority of the time, the reason the last unit is opposite to the others is so that at the termination point, the locomotive consist can run in the opposite direction without having to be turned around, either because such facilities don't exist at that location, or it's too time-consuming.

Answer 9

Because if one breaks down, the other one can power the train. the backwards one gives power to the working engine(s).the power engine is like a sibling helping out with the pulling or pushing.

Answer 10

i think it's because the engines don't actually power the train, they only charge the large batteries that power the train.