• Our booking engine at tickets.railforums.co.uk (powered by TrainSplit) helps support the running of the forum with every ticket purchase! Find out more and ask any questions/give us feedback in this thread!

Double-heading and Banking

Status
Not open for further replies.

Inversnecky

Member
Joined
1 Jan 2021
Messages
581
Location
Scotland
Can someone please explain to me about the technicalities of this. How does the driver ensure both locos are going at the same speed?

Presumably the second engine is controlled by the driver: but are the two linked so number two mirrors the speed or revs of the first? Or does each loco have its own driver?

What about variations in power, where settings are thought to be the same, yet one loco is outputting slightly more/less power than the other?

Thinking of banking, potentially you could have a rear loco pushing more than the front one is pulling, possibly causing a derailment.

Since this doesn’t happen, I’d appreciate hearing from those who knows how it all works in practice.
 
Sponsor Post - registered members do not see these adverts; click here to register, or click here to log in
R

RailUK Forums

StephenHunter

Established Member
Joined
22 Jul 2017
Messages
2,118
Location
London
Can someone please explain to me about the technicalities of this. How does the driver ensure both locos are going at the same speed?

Presumably the second engine is controlled by the driver: but are the two linked so number two mirrors the speed or revs of the first? Or does each loco have its own driver?

What about variations in power, where settings are thought to be the same, yet one loco is outputting slightly more/less power than the other?

Thinking of banking, potentially you could have a rear loco pushing more than the front one is pulling, possibly causing a derailment.

Since this doesn’t happen, I’d appreciate hearing from those who knows how it all works in practice.

With locomotives in multiple working set up, the first locomotive controls the second.
 

DelW

Established Member
Joined
15 Jan 2015
Messages
3,834
In the US, freight trains may have one or more unmanned locos mid-train and/or on the rear, controlled by radio signals from the leading cab. These may be up to about 3 miles from the controlling loco.

In steam days of course every loco had its own crew, with communication between them only by whistle signals.
 

Taunton

Established Member
Joined
1 Aug 2013
Messages
10,019
Double heading etc - quite simply it's the couplings that, like the rest of the train, keep it all together. Any variances of power are well handled inside that. If under multiple control and one loco, or the other, shuts down, there's just less power applied to the train. The USA have always been past masters at this, just applying as many locos to the front as the load requires. As locos have got larger there the old times of six, possibly even more, on the front have disappeared, but three or four of the latest and largest is still pretty much the norm.

Banking, unattached, at the rear is a bit different, but basically the banker just applies full power. There will be a neutral point in the train where vehicles behind have couplings in compression from the loco at the back pushing, and those ahead have couplings in pull from the loco at the front. This all adapts naturally as power and gradients etc vary - if in the train you may notice little shocks up and down.
 

Steve Harris

Member
Joined
11 Dec 2016
Messages
891
Location
ECML
Can someone please explain to me about the technicalities of this. How does the driver ensure both locos are going at the same speed?

The physical couplings between loco's along with both loco's working in multiple (an electrical connection system which sends the electrical control singnaĺ from the first loco to the second loco so the same amout of power is applied by each loco at the same time) sorts this out.

Presumably the second engine is controlled by the driver: but are the two linked so number two mirrors the speed or revs of the first?

Yes if both loco's are in Multiple (see answer above).

Or does each loco have its own driver?

If loco's are of different classes and can't work in multiple then each loco will have a driver, this is called working in Tandom.
 

43096

On Moderation
Joined
23 Nov 2015
Messages
15,164
Banking, unattached, at the rear is a bit different, but basically the banker just applies full power. There will be a neutral point in the train where vehicles behind have couplings in compression from the loco at the back pushing, and those ahead have couplings in pull from the loco at the front. This all adapts naturally as power and gradients etc vary - if in the train you may notice little shocks up and down.
The only time I've been on a train being banked has been out of Liege in Belgium. Here the process is that the train arrives and the banker then drops out of the holding sidings and buffers up to the rear. On receiving the 'RA' the driver of the train engine releases the brakes and the banking loco applies power to move the train: it's only when up to about 20km/h or so that the train engine applies power.
 

Whistler40145

Established Member
Joined
30 Apr 2010
Messages
5,911
Location
Lancashire
I've never been on a train where banking locos are required

I do remember that pairs of Class 37s would be on standby at Bromsgrove to bank heavy freight and the occasional heavy passenger train up The Lickey Incline, one train in the 80s was a Fridays Only Relief from Plymouth to Manchester Piccadilly that was booked for a loco change at Gloucester, a pair of Class 20s were booked to work forward and was booked for banking from Bromsgrove
 

GRALISTAIR

Established Member
Joined
11 Apr 2012
Messages
7,807
Location
Dalton GA USA & Preston Lancs
I have had the Lickey banker class 37 on the Bristol to Glasgow sleeper over 30 years ago. Also had a Class 25 over Copy Pit on a Merrymaker in the 1970s. If anyone is interested I am more than happy to post the dates and numbers.
 

themiller

Member
Joined
4 Dec 2011
Messages
1,056
Location
Cumbria, UK
Can someone please explain to me about the technicalities of this. How does the driver ensure both locos are going at the same speed?

Presumably the second engine is controlled by the driver: but are the two linked so number two mirrors the speed or revs of the first? Or does each loco have its own driver?

What about variations in power, where settings are thought to be the same, yet one loco is outputting slightly more/less power than the other?

Thinking of banking, potentially you could have a rear loco pushing more than the front one is pulling, possibly causing a derailment.

Since this doesn’t happen, I’d appreciate hearing from those who knows how it all works in practice.
A rear loco pushing more than the front occurs when the front power car on an HST shuts down. Nothing bad happens.
For freight, Eurotunnel trains are designed so that in the event of one loco shutting down, the other can still power the train out of the tunnel and into the terminal. This gives a stiff gradient and tight curves on a long train.
 

jopsuk

Veteran Member
Joined
13 May 2008
Messages
12,771
Thinking of banking, potentially you could have a rear loco pushing more than the front one is pulling, possibly causing a derailment.
Locos pushing trains with no loco on the front at all has been a successful thing for a long time, and serious derailments involving them have only happened when there's been something heavy on the line or the rails have broken
 

Irascible

Established Member
Joined
21 Apr 2020
Messages
1,988
Location
Dyfneint
A rear loco pushing more than the front occurs when the front power car on an HST shuts down. Nothing bad happens.

Although the risks are different depending on the type of coupler - knuckles or similar binding couplers can resist lateral & vertical force ( which is one reason buckeyes were introduced for passenger stock quite a long time ago ) whereas buffers ( especially with the couplers being actual loose chains - screw couplings at least limit travel a little ) do nothing to stop overrides & consequent locking.

Push-pull trains have been around an awful long time, the risks are well known. The US cut traction into the centre of trains because they might start pulling couplers apart if they stuck them all at the front.

I wonder how many broken couplings there've been on unfitted 3-link trains when the banker has dropped off a bit abruptly. Given the loose cut would roll back on the banker it would have at least kept them alert!
 

Cheshire Scot

Established Member
Joined
24 Jul 2020
Messages
1,331
Location
North East Cheshire
....and Beattock.

Railscot photo of diesel being banked by steam! https://www.railscot.co.uk/img/75/486/
Latterly it was a pair of class 20s crewed on three shifts by Carstairs giving 24 hour cover after Beattock shed had closed. I always assumed they ran light to/from Carstairs three times per day for shift change which would leave three windows each of one hour plus without bankers present - does anyone know if this was how it was worked in practice?

On trains departing Glasgow Queen St the practice was (as noted above) for the banker to start the train and quickly get to full power and the train engine then kicked in. Effectively in unscientific terms the train engine had the train weight on the drawbar and the banker had no weight behind it so (in theory) the banker should never get left behind. In earlier years they operated a form of slip coupling controlled from the banking loco (C15 tank engines) which obviously required the buffers to be compressed and the coupling slack. When this practice ended it meant any loco could bank as they were no longer coupled to the train.

Blair Atholl had a loco shed and trains used to be banked up Druimuachdar - I think they dropped back at Dalnaspidal where the gradient eased and there was a signal box and crossover, and Aviemore provided bankers to Slochd. I could be wrong but I think they also banked out of Forres towards Dava.

As noted by '43096' above, most loco hauled passenger trains out of Liege towards Brussels used to be banked, I can't remember the gradient but I think something like 1 in 38 or 1 in 40, and with the clear glass panels in the gangway connection one could look out from the rear coach and watch the banker - normally but not always electric - start the train and then nearing the top of the gradient drop back. On my most 'recent' visit back in 2010 when push pull operation with Driving Trailers had come in it was no longer possible to get the rear view but banking was still being practiced at least twice per standard hour. Some trains towards Aachen were also banked but this seemed to be less regular, presumably the gradient was less severe. I also recall being banked out of Aachen towards Liege, an interesting scenario of a Belgian crew on SNCB electric loco and German crew on a DB diesel (the voltage change being in Aachen station).
 
Last edited:

43096

On Moderation
Joined
23 Nov 2015
Messages
15,164
As noted by '43096' above, most loco hauled passenger trains out of Liege towards Brussels used to be banked, I can't remember the gradient but I think something like 1 in 38 or 1 in 40, and with the clear glass panels in the gangway connection one could look out from the rear coach and watch the banker - normally but not always electric - start the train and then nearing the top of the gradient drop back. On my most 'recent' visit back in 2010 when push pull operation with Driving Trailers had come in it was no longer possible to get the rear view but banking was still being practiced at least twice per standard hour. Some trains towards Aachen were also banked but this seemed to be less regular, presumably the gradient was less severe. I also recall being banked out of Aachen towards Liege, an interesting scenario of a Belgian crew on SNCB electric loco and German crew on a DB diesel (the voltage change being in Aachen station).
Banking is much rarer out of Liege now, unfortunately. Back in around 2011, there was a period around mid-day when three trains in the hour were banked in the autumn, necessitating three locos. As one of them came with a fresh crew from Kinkempois shed, it could be anything. I was fortunate enough to have a Type 77 diesel on more than one occasion, rather than the normal Type 23 electric at the time.
1610994461147.png
 

6Gman

Established Member
Joined
1 May 2012
Messages
8,383
I've long thought that, given the thousands of railway books published (many of them repetitive), a thorough study of banking on Britain's railways would be a worthwhile book.

Unless - of course - one exists!
 

Cowley

Forum Staff
Staff Member
Global Moderator
Joined
15 Apr 2016
Messages
15,688
Location
Devon
I have had the Lickey banker class 37 on the Bristol to Glasgow sleeper over 30 years ago. Also had a Class 25 over Copy Pit on a Merrymaker in the 1970s. If anyone is interested I am more than happy to post the dates and numbers.

I’ve also been banked up the Lickey by a pair of 37s (059 and 133 I think), we drew to a halt and they ran out of the siding behind us but didn’t couple up, then all three locos gave it the beans (47517 up front on 16 coaches) and as we eventually went over the top and started to accelerate away the 37s dropped off and presumably slowed to a stop before crossing over and running back down the bank ready for the next turn.
I’ve linked this clip before but it’s an absolute classic. Some quite enthusiastic crew members in the cab. :lol:

 

Whisky Papa

Member
Joined
8 Aug 2019
Messages
385
Miles Platting bank out of Manchester Victoria. Prior to the station being rebuilt, there was usually a station pilot / banker sat in one of the through roads. This was normally a Class 25 when I was spotting in the mid 1970s, which we saw deployed to assist eastbound freights fairly regularly. In later years, when I was occasionally passing through Victoria on family visits, I recall seeing a Class 60 in this role, which must have been fairly soon after they were introduced.
 

supervc-10

Member
Joined
4 Mar 2012
Messages
702
A rear loco pushing more than the front occurs when the front power car on an HST shuts down. Nothing bad happens.
For freight, Eurotunnel trains are designed so that in the event of one loco shutting down, the other can still power the train out of the tunnel and into the terminal. This gives a stiff gradient and tight curves on a long train.
And of course many other trains are push-pull with DVTs, such as IC225s or the assorted electric locos with DVTs on the WCML before the Pendolinos took over.
 
Status
Not open for further replies.

Top