Multiple working locomotives.

[CW2]

Class 25s were notorious for NOT working in multiple - even with other class 25s. I think some difference in the electronic control systems between 25/0 and 25/3 subclasses was the issue. So if you got a pair of 25s that were numerically close you stood a fair chance of getting to your destination, but if the numbers were 200+ apart then prepare for fight and sulking.
In Scotland the sight of three class 26s on a train was not uncommon, but by the early 1980s concerns over bridge weight limits caused a ban on running more than 2 locos together on a train. This applied throughout Scotland.

 

[GB]

Maximum of 5 locos.

Additional locos maybe conveyed over certain routes with special conditions applied by NR.
This is controlled using the Exceptional Load procedure with a 3973EXL form issued to give the necessary authority to the Driver/Signaller.

These moves came about with the need for FOCs to move locos around, usually at weekends, to cover for NR possession trains.

That is more for (as your name suggests) weight restrictions rather than "working in multiple". I have heard electric locos are restricted to two locos working in multiple both for energy consumption reasons and the affect of multiple pans in close proximity on the overheads.

== Doublepost prevention - post automatically merged: 6 Jan 2021 ==

Can locos dead in train (dit meaning?) still be used for braking?

Yes, DIT locos are effectively wagons.

 

[Journeyman]

Class 25s were notorious for NOT working in multiple - even with other class 25s. I think some difference in the electronic control systems between 25/0 and 25/3 subclasses was the issue. So if you got a pair of 25s that were numerically close you stood a fair chance of getting to your destination, but if the numbers were 200+ apart then prepare for fight and sulking.
In Scotland the sight of three class 26s on a train was not uncommon, but by the early 1980s concerns over bridge weight limits caused a ban on running more than 2 locos together on a train. This applied throughout Scotland.

Interesting - that makes sense, as later Class 25s had some of the earliest solid-state electronics in them, as opposed to the relays, magnets, valves etc. of the earlier ones. I guess the Blue Star standard wasn't particularly tightly defined, and stuff like varying voltages in the control wires could cause problems.

 

[Cowley]

Interesting - that makes sense, as later Class 25s had some of the earliest solid-state electronics in them, as opposed to the relays, magnets, valves etc. of the earlier ones. I guess the Blue Star standard wasn't particularly tightly defined, and stuff like varying voltages in the control wires could cause problems.

I’ve heard quite a few times of blue star locos not talking to each other properly and trying to go in opposite directions. Not sure of the cause though.

 

[Journeyman]

I’ve heard quite a few times of blue star locos not talking to each other properly and trying to go in opposite directions. Not sure of the cause though.

The "trying to go in opposite directions" thing can be quite common. Apparently it happened the first time a Class 483 was powered up after overhaul and refurbishment for Island Line, because the multi-working cables crossed in one of the intermediate vehicles in LU days, and no-one realised that a change was required when the trains were reduced to two cars.

 

[delt1c]

Class 25s were notorious for NOT working in multiple - even with other class 25s. I think some difference in the electronic control systems between 25/0 and 25/3 subclasses was the issue. So if you got a pair of 25s that were numerically close you stood a fair chance of getting to your destination, but if the numbers were 200+ apart then prepare for fight and sulking.
In Scotland the sight of three class 26s on a train was not uncommon, but by the early 1980s concerns over bridge weight limits caused a ban on running more than 2 locos together on a train. This applied throughout Scotland.

As was a triple 24/26 combinations on the Highland mainline, especially on the Night Highlander sleeper

 

[Richard Scott]

I’ve heard quite a few times of blue star locos not talking to each other properly and trying to go in opposite directions. Not sure of the cause though.

The only time I had 50s fail was when a pair wouldn't work in multiple, not just blue star that seemed to cause issues?

 

[3973EXL]

That is more for (as your name suggests) weight restrictions rather than "working in multiple".

Exactly, just trying to stop the thread going off topic with explanation for the number of locos permitted on moves.

== Doublepost prevention - post automatically merged: 6 Jan 2021 ==

I’ve heard quite a few times of blue star locos not talking to each other properly and trying to go in opposite directions. Not sure of the cause though.

Could be a problem with 37s, usually solved by swapping the jumpers over. I think probable cause would be a wiring fault in a jumper.

 

[Merle Haggard]

Unfortunately I can't remember the class concerned, but I'm sure I remember reading somewhere that there was a regular triple-headed diagram somewhere in early diesel days that needed two crews, because locos could only multiple work in pairs. Maybe Hymeks?

Sorry, that's not hugely useful!

In the 60's here was an Exeter - Newton Abbot late night passenger train that was booked for 3 D6300s - presumably, to get them all back to base. It was the working I mentioned above - 2 in mult. and the third in tandem.
When I saw it, a very rapid exit (in a fog of fumes) was made from Exeter, drivers keen to get home presumably, but very co-ordinated.

Which makes me wonder, would it have been possible for 4 of the single engined D6300 class to work in multiple? And if so did they?

I don't think so - see above note.

 

[CW2]

Mixed-class multiple working was sometimes a lottery, but usually entertaining for the enthusiast. There was a period when the 06:00 Glasgow Queen St - Fort William (with through coaches from Euston) was diagrammed to be worked by a steam heat 37 with either 20045 or 20085 inside - those locos being specially fitted with steam pipes for the purpose. They always seemed to work well together - probably because they were coupled in multi and tested on Eastfield beforehand. On the other hand I've had class 40s in multiple which had the inside loco cutting in and out at random.
My most memorable mixed pair was back in 1985. 37215 at Millerhill was needed at Dundee for weekend ballast train work, so it was multied up with 27041 to work the 1715 Edinburgh - Dundee. Normally when a 27 accelerates there is a burst of noise, then a falling in the engine note, then another chugging acceleration from low revs as the engine note builds up and speed increases. This time, with the 37 leading, the 27 was given no chance to rest, and was accelerated to maximum thrash virtually from standstill without overloading. The acceleration was quite striking, and the exhaust noise quite unlike anything I'd heard before.

 

[randyrippley]

I once at Weymouth saw a mixed bunch of five 33/0 and 33/1 being shunted/coupled together by an 03, and the blue star connectors joined on them all.
They had all gone five or so hours later - but I never saw them move so don't know if they left together.

== Doublepost prevention - post automatically merged: 7 Jan 2021 ==

Unfortunately I can't remember the class concerned, but I'm sure I remember reading somewhere that there was a regular triple-headed diagram somewhere in early diesel days that needed two crews, because locos could only multiple work in pairs. Maybe Hymeks?

Sorry, that's not hugely useful!

Lickey bankers

 

[Inversnecky]

Think I've seen a pic of four Class 76s fronting freight at Woodhead. Also two fronting, two banking, but don't know if there's ever been a case of four in front and two behind!

 

[SuspectUsual]

Didn't triple head 37s used to work in the Valleys on coal /steel?

3 x 37 in MU used to be used on Iron Ore trains in South Wales

And in Scotland too

 

[Llama]

I have heard electric locos are restricted to two locos working in multiple both for energy consumption reasons and the affect of multiple pans in close proximity on the overheads.

Our 331s give a constant real-time reading of the OHLE voltage on the TCMS (computer screen). I was sat in Preston last year when a freightliner rake hauled by 2x cl.90 locos started away northbound on the down goods line. The line voltage was showing about 23-24kV but soon dropped to just over 21kV, pretty much the lowest I've seen.