Consecutive pairs of units

[FGW_DID]

I do like a nice sequential pair, I’ve not yet managed a triple, but (contrary to what my colleagues think) I won’t go out my way and make unnecessary moves to achieve it but it is nice when it all falls into place.
Not quite the consecutive pair in the meaning of the OP but as there’s only two units allocated on the Bourne End line every day, this was sent to our chat group intimating I was responsible for these allocations:

165125: Maidenhead - Bourne End shuttles
165126: Marlow Donkey

For once I was an innocent party

Photo shows GWR Class 165 165125 & 126 in adjacent platforms at Bourne End.

 

[xotGD]

25th May 1988
37427 + 37428 1J24 Shrewsbury to Aberystwyth (but with Cardiff Canton only having six 37/4s, 426 to 431, a consecutive pair would nave been regular on this working)

Also 31146 + 31147 were a regular pairing on the Cambrian in summer 1992

I forgot to check for 37/4s...

21st June 1986 I had

37427 + 37428 Machynlleth - Aberdovey 1J20

 

[MCR247]

Tyseley depot reguarly send units out deliberately in consequetive number order all the time. Some of the staff like the challenge to get them shunted into pairs like that. You can tell its deliberate as some days they are all random then other days multiple units are consequetive numbers.

Tyseley have banged out a couple today.

I had thought it surprising how often paired 2 car XC 170/1s would be consecutive units but had just assumed it was down to it only being a small pool of 2 car units since the /5s got the centre cars added

 

[eastwestdivide]

In over 400 non-commute journeys, 3 have been consecutive pairs (158786+158787, 156418+156419 and 331025+331026).

And in over 900 commuting journeys, 8 have been consecutive pairs (150136+150135, 150135+150136, 150114+150115, 158870+158871, 158844+158843, 158844+158843, 150110+150109, 150126+150127)

The difficulty with 150s 156s and 158s for example is that they’re not all allocated to the same depot or even operator, so the number of potential pairs goes down substantially.

 

[pokemonsuper9]

The difficulty with 150s 156s and 158s for example is that they’re not all allocated to the same depot or even operator, so the number of potential pairs goes down substantially.

and that 150/156 pairs are very common in my area (although if I just looked for the last 2 digits there's probably some pairs that get added)

 

[boiledbeans2]

I know a shunter who, when noticing they had some sequential numbered units come in on separate arrivals that evening, would plan some overnight shunting that would just so happen to "coincidentally" see sequentially numbered units leave together in the morning. Not sure the depot drivers found it quite as amusing though

Tyseley depot reguarly send units out deliberately in consequetive number order all the time. Some of the staff like the challenge to get them shunted into pairs like that. You can tell its deliberate as some days they are all random then other days multiple units are consequetive numbers.

Do shunters decide which units go on which diagrams?
I would think someone would match the units to diagrams based on mileage, or to put a unit on a diagram which sends it back to a specific depot at the end of the day for maintenance.

 

[Falcon1200]

Do shunters decide which units go on which diagrams?
I would think someone would match the units to diagrams based on mileage, or to put a unit on a diagram which sends it back to a specific depot at the end of the day for maintenance.

It's been a while since I was responsible for allocating units (pre-privatisation!), but the methodology was indeed firstly, sets due for maintenance that day so that they finished at the depot, then units coming close to maintenance, so that they were presented with the correct between-exam mileage), and finally sets due for Heavy Cleaning. After that it was left to the yard staff, and they always wanted an easy life.

Mind you, on particularly quiet shifts TOPS office staff might ask for wagons to be shunted into numerical order; The reply was not affirmative, or printable.....

 

[Bow Fell]

Do shunters decide which units go on which diagrams?
I would think someone would match the units to diagrams based on mileage, or to put a unit on a diagram which sends it back to a specific depot at the end of the day for maintenance.

As a job I’ve done as a controller, we would compile a fleet maintenance plan based on depot maintenance requests, as well as our plans based on exam mileages, this would be emailed/faxed to the shunter.

We would ask for units to go specific diagrams so that they could return for maintenance / exam or have a note saying “short diagram or low mileage only”, add to this with non-multi or multi only units, there’s not much wriggle room for the shunters on what can go on what. But apart from that the shunters can allocate units as they see fit depending on the depot layout.

 

[td97]

Northern had 150123+150124 paired up 2 days in a row last week

Realtime Trains | 2N53 0822 Rochdale to Clitheroe | 12/11/2025

Real-time train running information for 2N53 0822 departure from Rochdale to Clitheroe on 12/11/2025. From Realtime Trains, an independent source of train running info for Great Britain.

www.realtimetrains.co.uk

Realtime Trains | 2N52 0721 Rochdale to Clitheroe | 13/11/2025

Real-time train running information for 2N52 0721 departure from Rochdale to Clitheroe on 13/11/2025. From Realtime Trains, an independent source of train running info for Great Britain.

www.realtimetrains.co.uk

 

[pokemonsuper9]

Northern had 150123+150124 paired up 2 days in a row last week

Realtime Trains | 2N53 0822 Rochdale to Clitheroe | 12/11/2025

Real-time train running information for 2N53 0822 departure from Rochdale to Clitheroe on 12/11/2025. From Realtime Trains, an independent source of train running info for Great Britain.

www.realtimetrains.co.uk

Realtime Trains | 2N52 0721 Rochdale to Clitheroe | 13/11/2025

Real-time train running information for 2N52 0721 departure from Rochdale to Clitheroe on 13/11/2025. From Realtime Trains, an independent source of train running info for Great Britain.

www.realtimetrains.co.uk

It looks like it stayed in the siding by Manchester Victoria overnight, so never made it to the depot to be potentially shuffled around.

 

[Flange Squeal]

Do shunters decide which units go on which diagrams?
I would think someone would match the units to diagrams based on mileage, or to put a unit on a diagram which sends it back to a specific depot at the end of the day for maintenance.

The depot in my example had around 30ish 4 car units arriving/departing each night/morning, in a real mix of 4, 8 and 12 car formations. It wasn't a maintenance depot, so everything that came in at night went back out the following morning (on weekdays - less trains were needed Sat/Sun nights, so some would spend a day or two there at weekends).

Control would send a list of several 'Requests' each night, for example specific unit(s) to be put out on a diagram that ended at a main maintenance depot that night. The number of requests varied night to night, but it's rare the night turn shunter didn't have relative free reign to make up the required formations the next day with at least 50-75% the units going out the next day, the remaining 25+ might be requests.

So if 001 was requested to be on an 8/12 car diagram ending at the maintenance depot that night, if they also had 002 and 003 on site without a request on them, then they could bung one or both on that too, for example. Sometimes you'd get 2/3 consecutive units with no requests at all giving you even more freedom to either put them all together, or on the branch line requiring two single units, have the branch worked by say 001 and 002 all day.

Sometimes you might not get sequentials, but you might still be able to play with things like say 011+022+033, or maybe at some TOCs with lots of the same class you could maybe do something like 001+011+111.

 

[boiledbeans2]

It's been a while since I was responsible for allocating units (pre-privatisation!), but the methodology was indeed firstly, sets due for maintenance that day so that they finished at the depot, then units coming close to maintenance, so that they were presented with the correct between-exam mileage), and finally sets due for Heavy Cleaning. After that it was left to the yard staff, and they always wanted an easy life.

Mind you, on particularly quiet shifts TOPS office staff might ask for wagons to be shunted into numerical order; The reply was not affirmative, or printable.....

As a job I’ve done as a controller, we would compile a fleet maintenance plan based on depot maintenance requests, as well as our plans based on exam mileages, this would be emailed/faxed to the shunter.

We would ask for units to go specific diagrams so that they could return for maintenance / exam or have a note saying “short diagram or low mileage only”, add to this with non-multi or multi only units, there’s not much wriggle room for the shunters on what can go on what. But apart from that the shunters can allocate units as they see fit depending on the depot layout.

The depot in my example had around 30ish 4 car units arriving/departing each night/morning, in a real mix of 4, 8 and 12 car formations. It wasn't a maintenance depot, so everything that came in at night went back out the following morning (on weekdays - less trains were needed Sat/Sun nights, so some would spend a day or two there at weekends).

Control would send a list of several 'Requests' each night, for example specific unit(s) to be put out on a diagram that ended at a main maintenance depot that night. The number of requests varied night to night, but it's rare the night turn shunter didn't have relative free reign to make up the required formations the next day with at least 50-75% the units going out the next day.

So if 001 was requested to be on an 8/12 car diagram ending at the maintenance depot that night, if they also had 002 and 003 on site without a request on them, then they could bung one or both on that too, for example. Sometimes you'd get 2/3 consecutive units with no requests at all giving you even more freedom to either put them all together, or on the branch line requiring two single units, have the branch worked by say 001 and 002 all day.

Sometimes you might not get sequentials, but you might still be able to play with things like say 011+022+033, or maybe at some TOCs with lots of the same class you could maybe do something like 001+011+111.

Thanks for the explanations! Sounds like a shunter is the perfect job for a trainspotter, choosing which units get coupled together.

 

[JKF]

Not units, but I once saw two consecutive Freightliner 66s crossing paths immediately in front of me on the NLL near Caledonian Rd. I was in exactly the right position to have had both locos in frame just before crossing each other, which itself was a very unlikely event. Sadly my phone battery was dead so it went unrecorded.

 

[xotGD]

So not only are 331002 and 331003 still paired up, but 331007 and 331008 are now together.

Is someone in Leeds or Skipton reading this thread?

 

[Peter Mugridge]

So not only are 331002 and 331003 still paired up, but 331007 and 331008 are now together.

Is someone in Leeds or Skipton reading this thread?

However, 331 015 and 331 016 are no longer together this morning...

 

[D1537]

So not only are 331002 and 331003 still paired up, but 331007 and 331008 are now together.

Is someone in Leeds or Skipton reading this thread?

And if you were at Leeds watching these, you could also see 195018+195019 on the Nottingham, then perhaps nip across to York for 801107+801108 to Edinburgh.

801/1 pairs are the only ones I can find recently (let's face it, with only 13 units and 3 diagrams for pairs every day they're not going to be rare).

Going way back in time I once had 33039+33040 on the Brighton-Plymouth. I've also had two consecutive 47 pairs (47406+47407 and 47421+47420) on a Pennine when Gateshead used to test locos off heavy maintenance that way, but since the train engine wasn't powering on those, I don't think that really counts.

 

[david l]

Several class 50's when in mutiple on the WCML between 1970 and 1974, far too many to list (but didn't have 400+401)!

 

[xotGD]

Just to say that 99001 and 99002 seem to be spending a lot of time together!

And on the Tyne and Wear Metro, 4001 + 4002 was always the best pairing to encounter.

 

[D1537]

And on the Tyne and Wear Metro, 4001 + 4002 was always the best pairing to encounter.

Although to be fair that wasn't a rare pairing since for quite some time they could only work with each other, 4040 and 4083!

 

[xotGD]

I've landed on another pair right now: 801107 + 801106 on 1D25

 

[Sonyman66]

I photographed 170116+170117 together at Long Eaton on 13/11/2025, then on 15/11/2025 170115+170116 were out together.

 

[Minilad]

Not quite consecutive but still a satisfying pair. Yesterday I had 172222/333 from Stratford upon Avon to Moor Street

 

[ValleyLines142]

158869+158870 still a pair, currently on the 0649 Wigan Wallgate to Leeds.

 

[150249]

Down in the South West, it is rather common to see a pair of 150s together, we have 232-234, 238-239, 243-244, 246-249 and 265-266. That is 8 different combinations. I seem to remember that a consecutive pair was involved in the Salisbury crash in 2021, being 158762 + 158763. Occasionally, the shunters are nice enough to supply a consecutive pair of IETs. I had 802004 + 802005 earlier this year.

 

[johncarter06]

Interesting topic. It does feel like consecutive-numbered units (e.g. 444 025 + 026) are turning up more than random chance would suggest though as some have pointed out, with large fleets the probability isn’t negligible. Whether it’s shunters/dispatchers having some fun or just statistical quirks, it’s a cool observation.

 

[Peter Sarf]

Interesting topic. It does feel like consecutive-numbered units (e.g. 444 025 + 026) are turning up more than random chance would suggest though as some have pointed out, with large fleets the probability isn’t negligible. Whether it’s shunters/dispatchers having some fun or just statistical quirks, it’s a cool observation.

Welcome to the forum.

I sometimes think something like a sub depot might have a small subfleet of consecutively numbered units. That would improve the odds in an otherwise large fleet.

 

[Wyrleybart]

We used to have a Bombardier fleet planner in our Control who really tried to get voyagers paired up consecutively. He disappeared off to Central Rivers and has probably since retired, but it is that role that probably achieved some of what you see.

 

[The exile]

25th May 1988
37427 + 37428 1J24 Shrewsbury to Aberystwyth (but with Cardiff Canton only having six 37/4s, 426 to 431, a consecutive pair would nave been regular on this working)

Consecutive pairings involving one of 427 - 430 presumably twice as likely as those involving 426 or 431.

 

[pokemonsuper9]

I sometimes think something like a sub depot might have a small subfleet of consecutively numbered units. That would improve the odds in an otherwise large fleet.

E.g. Northern 331/0s
001-012 are on the Leeds side
013-031 are on the Manchester side
Both have diagrams with paired sets.

 

[xotGD]

This morning 195122 + 195123 came off Blackpool carriage sidings together, but were then split in the station.

These were followed by 323217 +323218, which are still paired up in service.