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Thread: "Driving Coach" in the UK - what is the purpose?

  1. #1
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    Question "Driving Coach" in the UK - what is the purpose?

    More specifically, what is the purpose of a driving coach and a locomotive on the same train? Is it just to gain a small amount of power to run a specific route or to meet an extraordinary demand due to a holiday?
    Dick near Pittsburgh, Pa. i5-2500K 4.3ghz, 8gb memory, GTX1060 4gb video card

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    If it is the same as a cab car, it is a coach car that has one end reconfigured so an engineer can control the loco from the opposite end of the train. These units themselves have no power, but allow the train to operate in reverse, so the engineer can switch ends to always see in the forward direction of movement. In this configuration, the power pushes the train along the rails.
    "Cave Johnson. We're done here."

  3. #3
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    Here is a description originally provided by "borderriever" for my edification.

    BTP Steam Autocar
    North east England during the steam era. In 1905 the North Eastern Railway decided to use some surplus Fletcher BTP 0-4-4T locos built during the 1870s to power steam autocars.
    The objective was to save costs by eliminating the need to run around at terminal stations, which also permitted quicker turnarounds. The downside was a reduction in flexibility, particularly with
    strengthening, though some did run with a strengthening 6-wheeler. This meant that at the terminal destination a pilot loco had to remove the strengthener and switch ends so the driver could see
    on the return journey. If no station pilot was available then the steam autocar would have to run round the strengthener! the typical arrangement was the BTP situated in the middle of two driving van
    composites, though some services ran with a single Driving van composite.
    The company converted several bogie Third Carriages to Driving van Composites, designating them Diagram 116. Utilising 52ft carriages for the conversion meant that Third Class passengers did get
    a little extra legroom compared to that in the typical 49ft ordinary N.E.R. carriage. Compartments were 6ft 4 and a half inches long rather than the typical 5ft 11 and a half inches found in a 49ft
    carriage. First Class passengers were short-changed though. A 49ft carriage normally had a First Class compartment of 7ft 1 and a half inches in size. the single First Class compartment in the
    Diagram 116 was the same as the Third Class at 6ft 4 and a half inches, though it did have better upholstery than the Third Class, to give the illusion of premium travel.
    JackDownUnder

  4. #4
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    I would say that it is correct to say that a driving coach (more usually called a driving trailer to make it clear it is unpowered) is the same as a US cab car. They are most commonly used, as stated here, so that trains can be driven from the other end of the train to the locomotive. There are also some EMUs and DMUs where the motor coach is in the middle of the train that have driving trailers at both ends.

    Some examples include the Intercity 225 trains on the East Coat Mainline that have a Class 91 at one end and a Driving Van Trailer (DVT) at the other, the new Transpennine loco-hauled sock and Southern Region class 455 EMUs (Driving trailer at both ends).

    As JackDownUnder points out there used to be steam hauled trains with driving trailers. These were normally called "Auto Trains" and the associated riving carriages "Auto Carriages".

    Quote Originally Posted by maruffijd View Post
    If it is the same as a cab car, it is a coach car that has one end reconfigured so an engineer can control the loco from the opposite end of the train. These units themselves have no power, but allow the train to operate in reverse, so the engineer can switch ends to always see in the forward direction of movement. In this configuration, the power pushes the train along the rails.


  5. #5
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    Thanks - You wonder on the economics of hauling dead weight in one direction having a cost that they accounted for. Anyhow, that is a British Rail problem. Very interesting background.
    Dick near Pittsburgh, Pa. i5-2500K 4.3ghz, 8gb memory, GTX1060 4gb video card

  6. #6

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    The economics stack up because you are saving time running the loco round at the end of trip, and the cost of associated infrastructure that goes with that.

    In the case of the IC225 and the Mk3 stock used on the East Anglian services the DVT also carries parcels and contains the guard's compartment. Operationally replaced a parcels brake that used to be attached to the London end of most, if not all, West and East Coast mainline expresses so the trains got no longer.

    All the others I can think of have passenger accommodation as well as the driving cab.

    The biggest potential issue was safety - in the event of a head on collision you have a considerable weight of locomotive at the back, which with older designed body on frame stock would have caused, quite literally, carnage as the weight of the loco telescoped the carriages. Modern monocoque construction coaches can much better withstand the potential forces involved so that's no longer seen as an issue.

  7. #7

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    The Polmont disaster is a good example of having a light coach being propelled by a heavier loco and led to the addition of extra ballast and a cowcatcher to the front of the DBSOs.

    From a US point of view, CalTrain services would be an approximate equivalent to the sets running in the UK and Ireland with a driving trailer.

  8. #8
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    You only have to operate 'push-pull' passenger trains with a driving coach to immediately see the advantages. On my version of Middle Vale set in the early BR period the local passenger train services out at the more remote rural end of the route were operated by a push-pull set and not having to run around the train at the end of the journey made things very quick and easy. 2995Valiant has mentioned modern equivalents of the steam era push-pull sets, but I really don't know anything about those because I'm firmly a steam era woman.

    The driving coach is basically a coach with a driving compartment at one end with controls to operate the locomotive. There were various systems in use, some earlier designs were cable operated and some used either vacuum or air pressure to operate the controls. It's not powered, it's just a coach, the locomotive provides the power.

    Because the Trainz AI has more rocks in its head than usual over propelling a train of coaches it is impossible to operate a push-pull passenger service in Trainz without a little cheating. All my various driving trailers are set up as a faux locomotive. They don't have to have a lot of power, - in fact mine are rather weedy as locomotives, - all that is necessary is to convince the Trainz AI that the driving trailer is the locomotive when the passenger coaches are being propelled. With the driving trailer set up as a faux locomotive perfect station stops can be made every time at interactive platforms. I use the DMT platforms by Scottish, but I would imagine that others would work the same. The only essential thing about this conversion is to make sure that the engine script for the driving trailer has a maximum speed setting that is above the ruling speed limit for your line or the set speed limit in the passenger schedule or else the locomotive will be fighting against the driving trailer all the time.
    On Middle Vale I used a three coach set and the coaches are fairly heavy so the extra braking effect from the driving trailer was very welcome. On my GER Norfolk line I'm just using an engine and a driving trailer to operate a passenger service to a sleepy little branchline. Operating push-pull trains might not be everybody's cup of tea, but I have a lot of fun with it.

    Engine pulling the coaches. Middle Vales.


    Engine pushing the coaches. Middle Vales.


    Engine pushing the driving trailer. GER & (imaginary) minor railways, Norfolk.
    Narcolepsy is not napping.



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