So i have all ways wondered… The number of engines that is in consist, does that relate to the weight of the freight that is being hauled? Or do some company’s automatically put two units together? Also is their a rhyme and reason if their nose to nose, or nose to tail? in other words how their lined up?
Yup. Short light trains might have a single diesel. As the train got longer and heavier more units were added. If the train had to climb a grade, more diesels were added. There has been quite a power boost over the years. First generation (1940’s) diesels, F units, GP’s and so on had about 1500 horsepower. Later models like the GP-40 had 4000 horse. The latest biggest units have a good deal more. So a train that might have needed four F units in 1947, might only need two GP’s in 1970.
When consisting the only real rule is the front locomotive ought to be facing “forward” so the crew can see where they are going. “Forward” is obvious on covered wagons (F units), it’s the end with the windshield. GP’s are more slippery. Early GP’;s, GP 7 or GP9 were usually run long hood forward. The second generation GP’s were often run short hood forward, and the short hood was cut down below the cab windows to give the crew a better view forward. Except on some railroads, were the crews perferred to run long hood forward to put some metal in front of them in case of a crash.
Covered wagons on the old days were consisted with the lead unit facing forward and the trailing unit facing backward so when they got the the end of the line, the could run back to where they came from without turning the engines on a turntable, a time consuming process. If more than two units were needed, cabless “booster” B units would
Depends 
Number of engines (and how they are distributed) will be influenced by how much they have to pull, and how much strain the couplers can take. If a company is using four units at the front, four in the middle and four at the end of a long coal train, it is probably because they need that power.
It often makes sense to put engines tail to tail so you will have good visibility no matter which way the locomotive consist is moving. Some companies used to designate the long hood as front - since that offered better crash protection for crews.
Sometimes a local switcher will have two engines even if it doesn’t need it for power - perhaps even one loco at the front and one at the back of the train, to make it easier to head back without a runaround move, or to switch both facing and trailing spurs or something.
Sometimes railroads would send out two locos if they were in dire straits and had deferred maintenance for too long - hoping that if one unit died that other could finish the run.
It all depends on what situation you are trying to model, and what era. You certainly can defend putting two diesels tail to tail on a short train without anyone blinking.
Smile,
Stein
Interesting and informative responses.
Let me add a related question to the mix.
Did railroads try to consist identical types of locomotives or did they frequently mix different types of locomotives.
For example, would a railroad consist an E7 and an E8 together? This is something that I am contemplating with one of my roadnames.
Rich
Again, the answer is “it depends”
If you gotta mix to get enough power from what’s available, you mix. A couple of examples from a quick google search:
http://calzephyr.railfan.net/locos.html
http://www.frisco.org/vb/archive/index.php/t-6380.html?s=0adaf793b9efaecef7d7dba82127e2c6
OTOH, there could be other considerations that will keep a consist for a passenger train together.
For instance, for a period in history, there were agreements between the railroads and the unions that each locomotive would have it’s own crew (as had been the case with steam locomotives when you double or triple headed steam locomotives).
If you coupled together three random engines, you had three engines and needed three crews.If you bought a matched A-B-A set, connected (semi)permanently with draw bars instead of just coupled with couplers, and numbered the set e.g. 235A, 235B and 235C, then you had what under the rules needed just one crew.
Another issue was era and image. If you are modeling an era when the railroad took great pride in their new streamlined passenger trains, and where passenger locos would be painted in special colors, the railroad might try hard to keep a matched locomotive consist instead of a mixed locomotive consist. If you model an era when passenger trains was considered a liability the railroad preferably wanted to get rid of, anything that moved would be good enough.
A third consideration was what kind of passenger train you had - was it one of famous named trains, or some local passenger train way out in the m
I expect in the early years they tried to match E7’s and E8’s, though these two models were fairly close in appearance and operation. Passenger operations would likely try to keep a uniform appearance. In later years, they probably just used whatever was on the ready track at the roundhouse. I’ve seen photos of freight trains running F units, Geeps, and Alco’s all mixed together. 2 railroads were known for designating long-hood-forward and high-short-hoods long after most others had switched to low-noses and short-hood forward (N&W and Southern Railway). Mechanically speaking, diesel locomotives have no real forward or reverse, they are generally capable of running just as well in either direction. As noted before, the “F” (forward) designation indicates the direction the controls should face for forward operation, and was specified by the railroad. All diesel locomotives should have a small “F” on the side sills indicating which end is “Front”.
Brad
Many answers can be found here
Locomotive consist is built against the train tonnage and ruling grade…Of course extra locomotives could be added as a deadhead move since this didn’t require a crew like a light engine (aka power )move would.
As far as running the same types of locomotives together,in the early years yes,beyond that it didn’t matter as long as the locomotives had mu capabilities between builders.
I recall seeing a E8A/PA2 consist a PRR passenger train…
Another consideration that has not been mentioned is simply the movement of the locomotives themselves. I have seen nine locomotives on an otherwise unremarkable train. The reason: they want the locomotives someplace else on the railroad. And yes, they are all running, to haul them dead-in-tow would require different operating rules that might slow the train down.
You haul heavy coal trains from Wyoming to Chicago, you sure do not need the same number of locomotives to haul the empties back to Wyoming. Normally, the locomotives that went east would go back west again. Some times the “east” will snag one for its own use elsewhere. Eventually, these will have to be sent west.
Sometimes brand new locomotives are sent west, and eventually the old locos are lashed together and sent east for sale or rebuilding.
ROAR
Yes. One of my books explains how Southern Railway used some of their economy passenger trains, which stopped at nearly every little town it passed, to cycle locomotives to the shops for service. The train’s schedule was generous enough to allow for the 60 MPH top speed of the freight units.
(Don’t ask me to cite the book at the moment, it would take me more time than I have to look it up.)
Brad
It depends. Generally the number of engines is determined by the tonnage of the train, however the railroad still has to balance the power so often a train will have more horsepower than the tonnage requires. For example a coal train might need 3 or 4 engines loaded and only 1 or 2 empty, but the railroad will keep 3 or 4 engines on the train in both directions, so when the light empty train gets to the mine, it will have enough hp to pull the loaded train back out. Similarly the MoPac shipped a lot of chemicals off the Gulf coast so all the train heading north and east were heavy and all the trains heading south and west into the Gulf area were light. But they had to over power the S&W ward trains into the Gulf to have enough power to pull the next day’s loads back out. Intermodal trains are the same way. Stack rains tend to be heavy/loaded eatward off the Pacific coast and lighter/empty westward towards the Pacific.
It might simpler to say they power trains up for the heaviest direction on a route.
Depends again. If the set of power turns, that is when the set coming west into a terminal will quickly stand for a train heading east, they will double end the set. If the train is a high priority train with multiple units the first 2 units will most likely be facing forwards. That way if the leader goes down they have at least one forward facing unit that can be stepped up to the leader. If the set splits, in otherwards a train that is half Oakland and half LA gets to Salt Lake City and the ra
When railroads first bought road diesels, they generally bought F units and ran them in A-B-B-A sets, which were often were two sets of A and B units connected with a drawbar running back to back. In fact, the FT diesel was designed to be two units with a drawbar. Later, railroads often found three F’s were ‘just right’ for pulling mainline freight, so would match an A-B set of FT’s with an F2 or F3 A unit.
By running back to back, they didn’t have to worry about turning the units. However, normally (with a few exceptions) didn’t put more than two units together with a drawbar, since they sometimes had to move units onto a turntable to go into a roundhouse stall to be worked on, and three units wouldn’t fit on the turntable.
With later GPs, SDs, etc. it was “mix and match” to get the power you needed. As long as they had similar gear ratios, you could see an F-3, a GP-7 and an SD-9 all on the same train. If the consist was going to be together for a while, the railroad would try to make sure the ‘outside’ units faced away from each other, so the consist could be run more easily from either end.
E units of different types often worked together, for many years the standard power on Rock Island Rockets was an E-8A and E-7B.
BTW this was true for other makers too. Alcos, EMD, FMs etc. might all be together in a lash-up of diesels.
But, to borrow a phrase running thru this topic, ‘it depends’. The old Burlington Route often ran their E or F units “elephant sytle”, and here in the Twin Cities the Q used to run a regular transfer run with three EMD switchers all facing the same way.
WOW!!! Thank you everyone this has been very useful for me and my understanding of trains. I appreciate all the excellent feed back.
As built EMD 40 series, GP40/-2 SD 40/-2, were 3000 horsepower.
things are not always as they seem. step into the wayback machine to the days of the Penn Central. deferred maintenance had taken it’s toll on our locomotive fleet to the point that we often used 4 or 5 units on priority freight trains out of E St Louis when 2 or 3 would normally do. reason being, it was almost a sure thing that at least 2 units would fail before reaching Indianapolis.
really hot trains like TV-4 and TV-6 would get special attention. the roundhouse foreman’s clerk would do a computer search and the units having the least amount of road failures in the past 30 days would be cobbled together for the truck-trains. there was little time to turn anything on the turntable so as long as the lead unit was headed east, the rest just followed like trained pigs, regardless of how the were facing.
charlie
On the old Mopac we would put 5-6 GP18’s on the Ft Worth to Houston, Houston to Ft Worth trains in the hope that by the time they got to the other terminal they would still have 3 engines running.
On a more serious note, this was one of the last threads that Steinjr contributed towards. He will be missed.
On the Rock Island we felt the perfect consist was E7 and E8, with the E7 leading. The E7 cab was larger and quieter than a E8. Reason we liked them mixed was the E8 could get right out of town and up to 40 quicker than a E7, but over 40 the E7 started to gallop at a faster pace… Doesn’t seem logical due to the E8’s slightly higher HP but that’s what seemed to happen.
Dick Haave
Dick, thanks for that info on the Rock. I wonder if they did the same thing on the Wabash RR.
Rich
The C&NW’s passenger train from Chicago to Duluth-Superior often used an E-unit and an F-unit together back to back. Sometimes it would be a freight F-unit rather than a passenger F.
Great Northern’s Gopher and Badger trains between Mpls-St.Paul and Duluth-Superior usually was one E-7 and 4-5 cars, but during say a Christmas rush when they had a lot of cars and needed a more steam for heat, that it would add say a passenger GP (i.e. a high-nose GP that was equipped with a steam generator and water supply.)