A couple of questions regarding the AM10 and AM12 EMU's

[GS250]

Hi All

1) Were AM12's ever used on the London Midland? I recall seeing a few passing through Harrow and Wealdstone but possibly empty stock workings.

2) It was brought up on another thread that AM10's were rather leisurely in their acceleration, even for the period. The AM12's by comparison, not only had a higher top speed, but I recall were fairly quick off the mark too. I remember hearing in a cab ride video that an AM12 diagrammed to depart 3 minutes after an HST could often temporarily 'catch' the Tees Tyne Pullman on a double yellow from Kings Cross. Yet looking at the specs that had identical power output to the AM10's. What was the main difference as to their superior performance I wonder?

Cheers.

 

[SteveM70]

I’m 99% sure that the four class 312/2 units (which I think are AM12??) regularly turned up at Coventry in the early/mid 1980s on the Euston - Northampton - Birmingham stoppers

 

[Andy R. A.]

The 312s did work into Euston on passenger workings, mostly popping up on the services from Birmingham. Back at the end of 1978 one turned up on the 1921 from New Street, unfortunately the Driver to work it back on the 2205 Rugby wasn't conversant with 312s, another Driver had to be found to take the train out resulting in a 15 minute delay.
Something tells me the early batches on the LM were 75mph ?

 

[AM9]

The 312s did work into Euston on passenger workings, mostly popping up on the services from Birmingham. Back at the end of 1978 one turned up on the 1921 from New Street, unfortunately the Driver to work it back on the 2205 Rugby wasn't conversant with 312s, another Driver had to be found to take the train out resulting in a 15 minute delay.
Something tells me the early batches on the LM were 75mph ?

The 310s were all 75mph and I think that some of the 312s destined for LMR deployment were as well, although I don't thing the traction system itself was so restricted. When the 312s were introduced, there was criticism on the GE side of their 1.1mph/s/s acceleration, which was below the 1.3mph/s/s of previous EMUs. It was postulated that this was likely to present problems in the peaks. The reply from somewhere inside BR was that their use on intermediate services would allow higher cruising speed east of Chelmsford, resulting in a lower end-to-end transit time and allowed them to better interleave the class 47 hauled Norwich and Lowestoft trains.

 

[jfollows]

I’m 99% sure that the four class 312/2 units (which I think are AM12??) regularly turned up at Coventry in the early/mid 1980s on the Euston - Northampton - Birmingham stoppers

AM10 = 310
AM12 = 312
I use the "AM10" designation because that's what i grew up with in the 1970s. But technically it's wrong.
I mentioned elsewhere that AM10s substituted for E455 + ( so 100mph) timings on summer Saturdays between Manchester and Birmingham, which was because the normal rolling stock was used for summer Saturday extras, but I thought that they only kept to time because the E455+ schedules were generous. Also that Cheadle Hulme-Stafford was 85mph maximum at the time - it got increased later even before tilting trains.

EDIT Also I think that although the 310 EMUs were formerly officially called AM10s, the 312 EMUs came later and weren't ever officially "AM12" units, they were "class 312" from the start. I could be wrong though (as always!).

 

[43096]

Hi All

1) Were AM12's ever used on the London Midland? I recall seeing a few passing through Harrow and Wealdstone but possibly empty stock workings.

2) It was brought up on another thread that AM10's were rather leisurely in their acceleration, even for the period. The AM12's by comparison, not only had a higher top speed, but I recall were fairly quick off the mark too. I remember hearing in a cab ride video that an AM12 diagrammed to depart 3 minutes after an HST could often temporarily 'catch' the Tees Tyne Pullman on a double yellow from Kings Cross. Yet looking at the specs that had identical power output to the AM10's. What was the main difference as to their superior performance I wonder?

Cheers.

As built there were four 312s (312201-204) for the LMR, intended for Coventry-International-New Street-Wolverhampton stopping services and geared for 75mph (as opposed to other units in the class which were 90mph), though they no doubt escaped from time to time, and indeed would have had diagrams to get them back to Bletchley for maintenance.

They were renumbered 312727-730 and re-geared for 90mph when transferred away from the LMR.

 

[nw1]

Wondering how long the 312s could have lasted had there not been legislation against slam-doors? The very newest were built in 1978, which given the informal '35-year rule'* for EMUs, could have seen them lasting until 2013, perhaps even longer?

I did travel on a 312 once, but on the GEML so somewhat out of scope for this thread. It was an interesting shoulder-peak fast service to Colchester Town in 2001, think it was 1612 out of Liverpool Street.

*(not a documented thing, just based on my observation of the lifespan of first- and second-generation units on the South Western Division).

 

[8A Rail]

Both Class 310 and Class 312 units appeared on the Birmingham NS / Crewe / Liverpool Lime St service on an occasional basis in the late 1980's / early 1990's. I have a handful of images in my collection of them.

 

[GS250]

The 310s were all 75mph and I think that some of the 312s destined for LMR deployment were as well, although I don't thing the traction system itself was so restricted. When the 312s were introduced, there was criticism on the GE side of their 1.1mph/s/s acceleration, which was below the 1.3mph/s/s of previous EMUs. It was postulated that this was likely to present problems in the peaks. The reply from somewhere inside BR was that their use on intermediate services would allow higher cruising speed east of Chelmsford, resulting in a lower end-to-end transit time and allowed them to better interleave the class 47 hauled Norwich and Lowestoft trains.

Interesting that the 312s were actually not that fast on paper. I seem to recall them pulling out of places like Colchester and Romford at a fair pace.

 

[GC class B1]

From what I remember the AM10, class 310 were limited to 75 MPH because the B4 bogies did not have primary friction dampers and the ride was poor. Class 312 had primary friction dampers and were therefore able to run at a higher speed.
Some of the last class 312 units ran on the LTS (C2C)

 

[Sprinter107]

After 312 201 - 204 were transferred away, some other 312s arrived in the Birmingham area and cropped up not only on Liverpool trains, but also on local services. They were in NSE livery, but im not sure about the set numbers. I travelled on them a few times. It was around the time we got 308s.

 

[Magdalia]

2) It was brought up on another thread that AM10's were rather leisurely in their acceleration, even for the period. The AM12's by comparison, not only had a higher top speed, but I recall were fairly quick off the mark too. I remember hearing in a cab ride video that an AM12 diagrammed to depart 3 minutes after an HST could often temporarily 'catch' the Tees Tyne Pullman on a double yellow from Kings Cross. Yet looking at the specs that had identical power output to the AM10's. What was the main difference as to their superior performance I wonder?

I have a lot of experience of the class 312s on the GN. They were not very fast when compared to what followed. A train not stopping at Finsbury Park would do well to make more than 80mph on the climb to Potters Bar. I don't remember signal checks when following HSTs, but I do remember the class 312s filling up with HST fumes in the tunnels. The problem was more the class 312s delaying the HSTs, which is why they were replaced with class 317s.

 

[contrex]

Were class 312 emus ever called 'AM12' by anyone within BR? I know they were based on the emus classified AM10 in 1964/5 that were later given the TOPs class 310 designation. The AM series started in the 1950s, and as far as I know AM2 to AM11 became 302 to 311 (AM1 was withdrawn in 1966 before TOPS).

 

[edwin_m]

Something tells me the early batches on the LM were 75mph ?

I recall reading that in Modern Railways. I think they specifically mentioned them having different gearing compared with the GN examples, which would probably result in better acceleration.

Wondering how long the 312s could have lasted had there not been legislation against slam-doors? The very newest were built in 1978, which given the informal '35-year rule'* for EMUs, could have seen them lasting until 2013, perhaps even longer?

Quite possible, as according to Wikipedia they lasted as long as 2004. As well as being newer than the slam door units on the South Western, they were of a more recent design being more similar to the Mk2 than the Mk1 coaches, so may not have been subject to the crashworthiness-related ban on Mk1s.

 

[AM9]

I recall reading that in Modern Railways. I think they specifically mentioned them having different gearing compared with the GN examples, which would probably result in better acceleration.

Quite possible, as according to Wikipedia they lasted as long as 2004. As well as being newer than the slam door units on the South Western, they were of a more recent design being more similar to the Mk2 than the Mk1 coaches, so may not have been subject to the crashworthiness-related ban on Mk1s.

There's this picture of a farewell day with 312792 at Shoeburyness dated March 2003 but they might have been operating elsewhere. They were actually built in MKII bodies so embodied that series' integral body crashworthiness.

 

[Strathclyder]

Here is 312203 at Preston in October 1987 (copyright of Flickr's Martyn Hilbert) on a Lancaster-Birmingham New St working.

Class 312/2 EMU 312203 - Preston.

Class 312/2 Electric Multiple Unit 312203 calls at Preston with the Saturday Only Lancaster to Birmingham New Street Service on October 3rd 1987. This short-lived service employed one of the small class of 312/2s, four being constructed at York in 1976 for use between Birmingham New Street and...

www.flickr.com

And here is 312201 at Euston in August 1985 (copyright of Flickr's 6089Gardener) on a special duty (note the blind).

312201 EUS 17-8-85

On 17 August 1985, 312201 is seen at Euston. These units were not common at the south end of the WCML.

www.flickr.com

The 312s as a whole lasted well into 2004, the last examples being withdrawn by First Great Eastern that summer. Despite being withdrawn prematurely given their age at that time (anywhere between 25-28 years old, when a EMU tends to last between 30-40 years in service on average), the fact they were slam-door stock was undoubtedly the biggest factor in their early demise (being derived from the Mk2, they wouldn't have been subject to the crashworthiness-related bans on the Mk1s as @edwin_m points out above). Were it not for that, they could've lasted into the early 2010s at least as @nw1 said above.

*(not a documented thing, just based on my observation of the lifespan of first- and second-generation units on the South Western Division).

Not just in the South West, the Class 303s and 314s up here in Western Scotland/Strathclyde managed to last 42 and 40 years in service respectively; the 318s & 320s look set to match - or even exceed - this record.

 

[gg1]

Was consideration ever given to fitting the 312s with central door locking to allow them to remain in traffic? I'd have thought it would be a worthwhile exercise on units with 10 years of life left in them, unless being slam door wasn't the only problem with their use.

 

[Strathclyder]

Was consideration ever given to fitting the 312s with central door locking to allow them to remain in traffic? I'd have thought it would be a worthwhile exercise on units with 10 years of life left in them, unless being slam door wasn't the only problem with their use.

I'd be surprised if central door locking wasn't at least considered at some point, but, as you say, there were likely other factors at play that would've nulified the benefits such a modification would've delivered, thus it never happened. This is nothing but idle speculation ofc (lost count of how many times has that come back to bite me lol).

 

[nw1]

From what I remember the AM10, class 310 were limited to 75 MPH because the B4 bogies did not have primary friction dampers and the ride was poor. Class 312 had primary friction dampers and were therefore able to run at a higher speed.
Some of the last class 312 units ran on the LTS (C2C)

Wasn't there a time when the LTS had about 4 different unit classes in regular service, all very different in appearance? Perhaps 302, 312, 317 and 321?

 

[Magdalia]

The 312s as a whole lasted well into 2004, the last examples being withdrawn by First Great Eastern that summer.

Hertfordshire ran two "Grand Slam" railtours with class 312s on 06/03/04 and 13/03/04, see Six Bells for details.

Not just in the South West, the Class 303s and 314s up here in Western Scotland/Strathclyde managed to last 42 and 40 years in service respectively; the 318s & 320s look set to match - or even exceed - this record.

Class 313s managed almost 43 years on the GN. Class 317s are about 40 years old, depending on what you count as their start date.

 

[AM9]

Was consideration ever given to fitting the 312s with central door locking to allow them to remain in traffic? I'd have thought it would be a worthwhile exercise on units with 10 years of life left in them, unless being slam door wasn't the only problem with their use.

Central door locking on an outer suburban EMU would make peak services a hostage to fortune that one of the 46 slam doors on a 4-car unit might fail. Given that most outer suburban peak services on the GEML are 12-car, that's 138 retro-fitted mechanisms just waiting for their moment to fail. Dwells on peak services on the GEML are just too critical to risk that.
It's different on normal corridor express stock where there are four per car at the ends where most commuters would abort an attempt and slip through the vestibile to the next car.

 

[GS250]

And here is 312201 at Euston in August 1985 (copyright of Flickr's 6089Gardener) on a special duty (note the blind).

312201 EUS 17-8-85

On 17 August 1985, 312201 is seen at Euston. These units were not common at the south end of the WCML.

www.flickr.com

I'd almost certainly suggest that 312 unit at Euston was a 'football special' from the North. August would have been the 'Charity Shield' between Everton and Manchester United.

Not sure if I ever saw a 312 on a service train at Euston though.

 

[David Burrows]

Having had many years travelling on 312s between Colchester & Liverpool St, their acceleration was far superior to anything we had had on the GE previously. They were comfortable and warm, especially if one got in the corner behind the cab away from any draughts from any open windows. Wonderful units, eventually replaced by the 321s and 360s.

 

[A0wen]

I have a lot of experience of the class 312s on the GN. They were not very fast when compared to what followed. A train not stopping at Finsbury Park would do well to make more than 80mph on the climb to Potters Bar. I don't remember signal checks when following HSTs, but I do remember the class 312s filling up with HST fumes in the tunnels. The problem was more the class 312s delaying the HSTs, which is why they were replaced with class 317s.

That wasn't the only problem - don't forget when the 312s were ordered there were only 25 of them to cover the GN electrification - IIRC a 3 tph service between Kings Cross and Royston (2 stopper, 1 fast).

Electrification extended to Huntingdon in 1986 and Cambridge in 1988 - this necessitated the building of extra units, originally the 317/2s (20 of them) and then in 1989 the 48 x 317/0s were also transferred to the GN - so the GN ended up with far more units, that was probably a greater consideration. Also the GN route was being moved to OMO - which meant the 312s would have had to go as they couldn't be operated in that way, whereas the 317s were designed for OMO and the 313s on the inner required limited change to accommodate it.

 

[JonathanH]

The last 312s on the GE had some doors locked up in the last few years. As much as anything, I suspect a desire to run more services DOO was another reason for their withdrawal.

There was a story at one point about trying to get peak time commuters to have a second job where they acted as guards on GE services that only did peak diagrams. I'm not sure how serious it was but it never actually happened.

 

[jfollows]

Were class 312 emus ever called 'AM12' by anyone within BR? I know they were based on the emus classified AM10 in 1964/5 that were later given the TOPs class 310 designation. The AM series started in the 1950s, and as far as I know AM2 to AM11 became 302 to 311 (AM1 was withdrawn in 1966 before TOPS).

My recollection, which I mentioned in post #5 above also, is that "AM12" wasn't ever an official designation, in agreement with you I think. I refer to "AM4" and "AM10" because that's what they were when I used them regularly south of Manchester between September 1970 and March 1980.

 

[Magdalia]

That wasn't the only problem - don't forget when the 312s were ordered there were only 25 of them to cover the GN electrification - IIRC a 3 tph service between Kings Cross and Royston (2 stopper, 1 fast).

The original GN fleet was 26 units, but 312726 was sent to the GE after Hornsey found that they could deliver higher fleet availability than what was in the planning assumptions.

Electrification extended to Huntingdon in 1986 and Cambridge in 1988 - this necessitated the building of extra units, originally the 317/2s (20 of them) and then in 1989 the 48 x 317/0s were also transferred to the GN - so the GN ended up with far more units, that was probably a greater consideration.

20 units 317349-368 replaced class 312s on the Royston trains. 317369-372 were ordered separately for the Huntingdon/Peterborough electrification in 1986/87, but they weren't ready in time, and the interim service to Huntingdon was class 312s. The Cambridge electrification was covered by bringing in units direct from the Midland that had been replaced by class 319s. 317337-348 were already on the GN in time for electrification to Cambridge in May 1988, and some class 312s remained on the GN until then. There's a small number of known class 312s workings to Cambridge after the OHL from Royston was energised.

Also the GN route was being moved to OMO - which meant the 312s would have had to go as they couldn't be operated in that way, whereas the 317s were designed for OMO and the 313s on the inner required limited change to accommodate it.

Good point! I remember the strikes in the summer of 1985 about the introduction of OMO.

 

[GS250]

I have a lot of experience of the class 312s on the GN. They were not very fast when compared to what followed. A train not stopping at Finsbury Park would do well to make more than 80mph on the climb to Potters Bar. I don't remember signal checks when following HSTs, but I do remember the class 312s filling up with HST fumes in the tunnels. The problem was more the class 312s delaying the HSTs, which is why they were replaced with class 317s.

Dare I say any double yellow encountered by a 312 following an HST would have been very early on in the 'chase'. Quite clearly an HST would pull away at anything over 60mph.

Interesting that the 317s, of which were no doubt faster overall were rated at a similar output to the 312's. Probably better tech and being lighter would have helped? Once the line was electrified to Peterborough I believe there were 'fast' 317 diagrammed units that could maintain 100mph for most of the journey North of Potters Bar.

 

[Magdalia]

Dare I say any double yellow encountered by a 312 following an HST would have been very early on in the 'chase'. Quite clearly an HST would pull away at anything over 60mph.

Interesting that the 317s, of which were no doubt faster overall were rated at a similar output to the 312's. Probably better tech and being lighter would have helped? Once the line was electrified to Peterborough I believe there were 'fast' 317 diagrammed units that could maintain 100mph for most of the journey North of Potters Bar.

Class 317s went up to Potters Bar at 90 mph, unless they were following a class 91. Fast trains to Peterborough with class 317s were special, with 100 mph in the dip at Hatfield and then down the hill from Stevenage. If the first stop was on the fast line at Biggleswade or St Neots then start to stop times from Kings Cross in excess of 80 mph were achievable. Class 317s were noticeably faster than the class 321s which came later; class 321s were about halfway between class 312s and class 317s, going up to Potters Bar at about 85 mph.

 

[gg1]

Central door locking on an outer suburban EMU would make peak services a hostage to fortune that one of the 46 slam doors on a 4-car unit might fail. Given that most outer suburban peak services on the GEML are 12-car, that's 138 retro-fitted mechanisms just waiting for their moment to fail. Dwells on peak services on the GEML are just too critical to risk that.
It's different on normal corridor express stock where there are four per car at the ends where most commuters would abort an attempt and slip through the vestibile to the next car.

Fair point, hadn't considered that.

The Chiltern 121 and Lymington 3CIGs probably had a similar ratio of doors to carriage but the odd locking failure on a relatively lightly used route isn't a major problem.