Atomic Systems

Something that has always vexed my tiny brain is how multi-loco setups were handled before the days of electronic control relaying.

I assume in the days of steam it was some black art that drivers learned, but even so, how would they handle it to make sure both loco's were pulling equally?

And what of top and tail setups, how the heck could the rear driver (be it steam or diesel) match what he is doing to what is happening at the front of the train (though I assume braking would be controlled solely from the front cab).

Any wisdom from some of the venerable kettle (and ye olde diesel )pilots on here?

You had two drivers who essentially relied on route knowledge to get it right - a very skilled profession back in those days!

Top & Tail operation normally has the rear loco "dead". I imagine that if it's T&T because the back one is banking, both engines will be pushing as hard as they can. I don't think the rear engine would have been coupled to the train though.

wasn't it done partially with whistle codes back in the steam era?

the one that's puzzled me for a while is how GWR autocoaches worked...

Top and Tail was not allowed before the mid 1990s. Even now it usually need control's permission and is only done where an alternative way of working cannot be found.
It costs money and fuel if the 2nd loco is crewed and adds weigh if it is not so it is avoided when possible.
Top and tail usually attracts the photographers so magazines can give a false impression of how common it is.


Banking on gradients was done by experience.

The train loco would power enough to stop running back and wait for a push and a whistle.
They would then set off and both would power by feel only.
Banker drivers knew where the signals were and they were sited where they could be seen or repeaters were used.

Bankers were rarely coupled on and would drop off at the summit.

A lot of banking was undertaken between Rowsley and Peak Forrest on the old Midland route, more to reduce stain on the couplings than anything else, on unfitted freights in steam days.
I've seen it reported the in order to ensure the engine crew on the back were pulling their weight (should that be pushing) when entering tunnels the train engine crew would throw a tyre into the firebox. This had the effect of making the crew at the back want to get out of the tunnel as quickly as possible.

Richardtysoe wrote:wasn't it done partially with whistle codes back in the steam era?

the one that's puzzled me for a while is how GWR autocoaches worked...

The auto coach iirc was very slack i went on it at the SVR a few years ago and its an Animal to control plus if the driver pulled the whislte to hard the loco would carry on whistling, then when that happens the fireman resets the whislte.

thegoonden wrote:how multi-loco setups were handled before the days of electronic control relaying.

You would have had a driver in the lead locomotive (this would be termed the leading, assisting or pilot locomotive), and another driver in the second locomotive (which would be termed the train locomotive). The train locomotive is always the locomotive at the lead of the train that is attached to the train, all other locomotives are assisting.

The right away from the guard is always given to the rear locomotive first, and then the front locomotive, it is then up for the drivers to signal to each other that it is ok to proceed. The train locomotive will provide the power unless he requests assistance from the assisting locomotive, or unless both drivers have come to a prior agreement as to when the assisting locomotive will provide the power. This is the same for both steam and diesel locomotives, whatever formation they are in.

thegoonden wrote:And what of top and tail setups, how the heck could the rear driver (be it steam or diesel) match what he is doing to what is happening at the front of the train (though I assume braking would be controlled solely from the front cab).

Exactly the same here, train locomotive provides the power, assisting locomotive should only provide power if a prior agreement has been arranged, or if the train locomotive driver whistles up for it.

Richardtysoe wrote:the one that's puzzled me for a while is how GWR autocoaches worked...

The driver would have had a control in the cab of the autocoach which is linked to a rotating shaft below the running floor of the coach, which linked with another rotating shaft that ran the length of the coach which controlled the regulator on the locomotive by another rotating shaft. The driver had controls for the regulator, whistle and brakes, but he had no control over the reverser, so that was the firemans job. Very simple really, certainly simple compared to the air method of other railways which required extras such as westinghouse pumps.

Equally though, with the mechanical method you were limited in the amount of vehicles you could have, which was 4 plus a locomotive (which would be in the middle), as you would be pulling quite a lot to operate the regulator, any more than 4 and it became very very difficult to work, generally though I think they would have worked with two autocoaches, one either side of the locomotive.

Just to add to banking, it was a very tricky thing to get right, on some occasions the train would proceed at quite a speed at the banker locomotive would run quite fast to catch up with the train and shove it up the hill, I believe this method was in operation on the Lickey Incline as late as the 1980s.

Ta muchly everyone.
Sounds like a tricky endeavour all round.

Those autocoaches seem very odd, I had now idea there was such a thing as a "driving trailer" for steam until I seen the autocoaches and (I think) another type of a simillar thing here in MSTS.

(Growing up in NI in the 70's and 80's has made me a wide eyed innocent in terms of railways and their wiley ways).


EDIT: and I never imagined (OT though it is) that anything like Leader existed in reality.....thought it was just a creation of schoolboy dreams.