One reason/excuse given for the axing of the APT was that they could only use one pantograph, for the reasons you gave. The first would disturb reliable contact with the second. That resulted in a centrally located drive unit, essentially meaning you needed 2 buffet cars guards etc.
No, not really. That's why they had turntables. The new steam engine was backed on to the outbound part of the train, the train would leave leaving the inbound loco behind to shuffle off to the turntable. Until remote controlled locos were available, the driver sat at the front of the train with the engine.,
Some teeny little one coach branch lines had an engine thgat 'pushed' teyh train, but no mainline stuff
That is not 'reversing out'. Multiple connected power units have no 'reverse'
^ to 8 coaches.
You are sort of both right. Standard layout would apply on main lines, but many of the little branch lines did not have turntables at the end. Sometimes the engine would "change ends" via a parallel line and two sets of points.
Only time I can recall that was with tank engines where you can see out of the back pretty well.
They would pull trains 'back to front'.
I cant remember ever seeing an engine 'push' a train. Other than shunting.
We're in danger of violently agreeing again. It was always tank engines on our local line and, like I said, they changed ends but without a turntable. Shouldn't have said sometimes; but many of our local historic pictures do show shunting.
Tank engines were more designed to go either way? I'm not sure a mainline engine with tender would be happy at full speed in reverse?
[1] That's why I said, "They had an elaborate turntable big enough for the engine plus tender." I know that branch lines used tank engines, which can easily go in reverse. [2] In a still picture, how can you tell which way it is going?
(a) You wouldn't be able to see where you are going past the tender; and (b) it wouldn't be possible to change crews on long journeys. (Tenders can have narrow corridors connecting to the first car.)
The first solution to the "reversing problem" is to reverse the whole train: you can have an engine each end (though the one at the back might be redundant); or a cab each end if the power units (diesel or electric) are slung under the passenger cars. (It appears that this is only done with short distance/slow trains.)
Or you can move the engine to the other end of the train on a side line. (I suspect this would be done after it is shunted out of the terminus.) There used to be diesel locos with a cab at both ends. Early electric locos on the London Underground were double ended, before the Yanks twigged that the individual cars could be powered, and all controlled from cabs at either end.
Or don't reverse it. There may be islands where the trains go round and round without reversing. And the London Circle Line used to go round and round (as its name might suggest). (I don't know why they have discontinued this; it was useful as it didn't matter too much if you got on the train in the wrong direction: it only took 45 minutes to go all the way round.)
The summer "tourist train" from Fort William To Mallaig manages it on the way back. But, the line isn' as straight as some.
This is the norm: the fastest trains in the world have a cab each end and never change the order of the vehicles. TGVs have most of the power in axles near the front of the train (more like a traditional locomotive), but others have distributed traction motors along the length of the train. ICE, CRH, etc have passenger capacity in the leading vehicle.
That is very rare these days, at least in the UK. More common on the Continent, where eg locos are swapped at borders with different electrification or signalling standards. Almost all trains are now fixed formation multiple units. Shunting passenger stock is unusual except for things like sleeping cars.
Almost all diesel and electric locos have a cab at each end. Multiple unit trains can be formed of several units, with unused cabs in the middle. (also some LU stock)
You can also put the cab in the middle, as with:
Some tram systems have a 'balloon' loop where the vehicles can turn around at the terminus - means you get more passenger capacity in the vehicles.
The 'Merry Go Round' system for coal trains also relied on this - saved time having to run round the loco as the train could run in a continuous loop mine-power station-mine without stopping.
Theo
Generally, the smoke goes backwards
I think because of the difficulty of removing a faulty train.
I am sure my car or van causes more NOX pollution by me having to slow down for the speed camera and then accelerate hard before slowing down again for the next speed camera.
Junctions 33 to 34 of the M1 but this does change from day to day.
Called a run around
Oh that and the brakes didn't work.
Tender locos were/are limited to 40mph/45mph when running in reverse. It is always preferred to turn them the right way around, but not a requirement.
Some tender locos even had a separate extension of the loco's cab, with its own screen and narrow tender tops (Ivatt 2MT 2-6-0 [not the 2-6-0T] for instance) to provide better protection and visibility for the crew and here's one running backwards
These could be formed as one or two carriages, with a loco at one end, that pulled them in one direction and then pushed them in the other, with the driver having moved to the cab in the end carriage or two to four carriages, with the loco sandwiched in the middle, pushing and pulling and driven from a carriage at the front end in either direction.
More recently ('80s?), some Scottish express services were run with a loco at one end and a specially converted carriage with a cab at the other. These ran at express speeds, with the loco pushing when running in one direction.
These days there are also DVTs (Driving Van Trailers) used this way and the mk4 is rated for 140mph!
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