Introduction of Mark 2Z/A/B/C stock

[Taunton]

The Mark 2 Pullmans being vacuum braked only were part of the reason the Liverpool Pullman was withdrawn in the mid-1970s. BR supposedly didn't have workshop capacity to convert them to air braked

One air brake conversion that was done was of the Mk2z transferred to Scotland for the introduction of the Push-Pull service from Glasgow to Edinburgh in 1971. These were given this substantial enhancement at St Rollox works, who seemed to be expert in this type of change. I once experienced (described elsewhere here) a blistering stop when late eastbound into Haymarket, from full speed (supposedly 90mph) into the Edinburgh suburbs, brakes hard on, relief valves heard to be operating, pulled up JUST at the far east end of the platform. Impressive.

The Mk 2z were dual heated, they had been almost wholly ETH initially out of Euston, but when transferred to Scotland it was back to steam heat for a couple of years until some of the Class 27 were made ETH capable. This caused all sorts of initial issues where the ETH kit had not been used for a while, burning smells, blown fuses, etc, until finally sorted out.

 

[AY1975]

A Mk 2Z was tried out in a Cobbler set soon after the working was introduced but the daily mileage (about 132!) was insufficient to keep the batteries charged so the forced air ventilation didn't work - it was cold! Surprised the same problem didn't occur on the Oxford _ Paddington NSE commuter trains

Or on other services that were formed of mixed Mark 1 and 2Z sets, such as Southampton and Weymouth boat trains (which usually had a Mark 2Z Corridor First providing the 1st class accommodation and 2nd class being all Mark 1s) and the East Grinstead and Uckfield commuter workings (ditto, in fact I believe that these were formed of sets from the same pool as the Southampton and Weymouth boat trains).

 

[edwin_m]

One conversion that was done was of the Mk2z transferred to Scotland for the introduction of the Push-Pull service from Glasgow to Edinburgh in 1971. These were given this substantial enhancement at St Rollox works, who seemed to be expert in this type of change. I once experienced (described elsewhere here) a blistering stop when late eastbound into Haymarket, from full speed (supposedly 90mph) into the Edinburgh suburbs, brakes hard on, relief valves heard to be operating, pulled up JUST at the far east end of the platform. Impressive.

They were air-braked with disc brakes, making them I believe the only disc-braked Mk2s and the only air-braked Mk2Zs, although other stock such as the 310s had disc brakes on the same B4 bogie type. Disc-braked stock is generally capable of 9%g braking, compared to 7%g for tread brakes.

 

[Beebman]

Or on other services that were formed of mixed Mark 1 and 2Z sets, such as Southampton and Weymouth boat trains (which usually had a Mark 2Z Corridor First providing the 1st class accommodation and 2nd class being all Mark 1s) and the East Grinstead and Uckfield commuter workings (ditto, in fact I believe that these were formed of sets from the same pool as the Southampton and Weymouth boat trains).

Back in 1980 I travelled from Reading to Manchester Victoria (with a DMU forward to Rainhill) on a BR ADEX for the Rocket 150 event which had started from Southampton and as far as I can remember it was a boat train set - there were no reservations and I managed to grab a seat in one of the 2Z FKs. I also rode in one, which had been transferred to the ER, from Liverpool St to Cambridge in 1988 not long after electrification with an 86 on the front (and both times I remember the Mk.1 style interiors).

 

[hexagon789]

They were air-braked with disc brakes, making them I believe the only disc-braked Mk2s and the only air-braked Mk2Zs, although other stock such as the 310s had disc brakes on the same B4 bogie type. Disc-braked stock is generally capable of 9%g braking, compared to 7%g for tread brakes.

The concept was tested on a Mk2A set used on The Talisman.

Tread brakes are 6%g average from 100mph deceleration by the W curve which was based on vacuum braking with 1/16th of brakes isolated.

Sprinters with tread brakes are 7%g from 75mph.

The Mk2Z were equipped with two-stage brakes - 9%g to 60mph, 6%g over 60mph. (Not unlike the HST power cars until 1985, though the figures were slightly different.)

Even Mk3s had different distributor ssettings depending on use. HST trailers were always 9%g, but the Mk3A were initially reduced to 6%g to match the tread braked Mk2s and Mk1 full brakes/catering they frequently ran with on the WCML, before being increased back to 9%g when 110mph running was introduced.

The Mk3s used on the E&G push-pulls were quickly adjusted to 9%g before entering passenger service to meet the heavy braking demands.

 

[43096]

The Mk3s used on the E&G push-pulls were quickly adjusted to 9%g before entering passenger service to meet the heavy braking demands.

I assume the DBSOs were also 9%g?

 

[hexagon789]

I assume the DBSOs were also 9%g?

Yes, though only the disc braked ones of course.

There were issues during initial testing with delay in a brake application be being made in the DBSO, to the 47 on the rear responding, resulting in a some station overruns during handling turns.

Consequently different springs were fitted to the distributors on the DBSOs and Mk3s to enhance braking performance, but officially the braking rate was 9%g - in practice it may have been higher.

 

[Clarence Yard]

This may have had some mk1's in it, but was certainly mainly mk2 - and yes it was in NSE livery

Iirc, that was an RR Edge Hill set comprised of ex NSE vehicles.

The cobbler sets were all Mk1 and they ended up at the Oak on the Oxfords together with the ex Cambridge/Lynn Mk2 sets. About half the Oxfords were used all day so they didn’t have the same problem with batteries as the cobblers did on the WCML. The rest used to layover at the Oak in the carriage and they used to get daily attention. Sets weren’t fixed so shunting in and out of vehicles for/from repair was quite common.

Regional Railways picked up a lot of NSE stock in the late 1980’s/early 1990’s but at the end of VB LHCS at the Oak, a very high proportion were just sold off for preservation. The Mk 2 BSO, TSO and FK vehicles were popular purchases.

 

[Helvellyn]

Yes, though only the disc braked ones of course.

There were issues during initial testing with delay in a brake application be being made in the DBSO, to the 47 on the rear responding, resulting in a some station overruns during handling turns.

Consequently different springs were fitted to the distributors on the DBSOs and Mk3s to enhance braking performance, but officially the braking rate was 9%g - in practice it may have been higher.

9711-9713 only had tread brakes didn't they?

 

[hexagon789]

9711-9713 only had tread brakes didn't they?

Correct.

9701-10 were the original 10. Disc braked

9711-13 were conversions for extension of push-pull to all Glasgow/Aberdeen services from May 1985. Tread braked

9714 was the replacement for 9706 lost in the Polmont accident in 1984. Disc braked

 

[nw1]

Could you have easily distinguished a 2Z by sight?

I have to admit the only Mk-II distinguishing features I remember were non-aircon versus aircon, but as I spent time at Reading in the 80s on multiple occasions it seems likely I would have seen 2Zs.

== Doublepost prevention - post automatically merged: 14 Mar 2026 ==

Certainly in the mid to late 80s there were express NSE services to both Oxford and Newbury throughout the day.

Indeed: the 1989 Paddington working book is available on the BR Coaching Stock groups.io group and reveals basically an hourly service to Oxford and two-hourly to Newbury. There was some interworking between routes.

The off-peak (0900-1700) allocations on the Oxford and Newbury routes were as follows:

0915 Manchester Air-braked Polmadie IC Set
1015 Oxford Air-braked
1036 Stratford HST
1047 Newbury Air-braked
1115 Worcester HST
1215 Oxford Vacuum Set OM108
1240 Newbury Vacuum Set OM204
1315 Oxford Vacuum Set OM105
1415 Oxford Air-braked
1440 Newbury Air-braked
1515 Oxford Vacuum Set OM203
1615 Oxford Vacuum Set OM204
1647 Reading (only) Vacuum Set OM107
1657 Derby Longsight IC Set - as an aside, bizarrely skipped Reading (non-stop Oxford) - not even a pick-up call - a very rare thing for an XC service to do

I would guess the OM1xx were Mk-I sets and the OM2xx were Mk-II 2Z sets.

As an aside the Oxford services regained clockface timings by this time, I seem to remember them being a bit erratic in terms of departure times for a while in the mid-80s.

 

[Magdalia]

Could you have easily distinguished a 2Z by sight?

I have to admit the only Mk-II distinguishing features I remember were non-aircon versus aircon, but as I spent time at Reading in the 80s on multiple occasions it seems likely I would have seen 2Zs.

MarkIICs were easily distinguishable because they had wrap round end doors.

"Plain vanilla" MarkIIs were distinguishable from MarkIIA and MarkIIB by the absence of air brakes, except for the Scottish push pull vehicles, which were distinguishable in other ways.

Of course it was always possible to cross check the vehicle numbers!

Knowing which sets were air braked and which were vacuum braked was very important operationally.

 

[Sun Chariot]

Could you have easily distinguished a 2Z by sight?

Externally, the Mk2 "first variant" had Mk1 style end-gangway connections: and the early batches (all FK, many TSO) were fitted with 4-piece passenger window top-lights - very similar to Mk1 but in a wider glass pane*.
Internally, the materials and fixtures followed Mk1 practice of 1963-1964.

* The exception being Mk2 FK prototype 13252's passenger window panes of similar width to Mk1.
Here's its interior (pics found after a quick internet search):
https://www.flickr.com/photos/elettra1143/6900033428/in/photostream/
https://www.flickr.com/photos/elettra1143/6900038410/in/photostream/
https://www.flickr.com/photos/elettra1143/7046133499
And exterior:
https://www.flickr.com/photos/elettra1143/7046128371/in/photostream/

 

[Beebman]

Externally, the Mk2 "first variant" had Mk1 style end-gangway connections: and the early batches (all FK, many TSO) were fitted with 4-piece passenger window top-lights - very similar to Mk1 but in a wider glass pane*.
Internally, the materials and fixtures followed Mk1 practice of 1963-1964.

* The exception being Mk2 FK prototype 13252's passenger window panes of similar width to Mk1.
Here's its interior (pics found after a quick internet search):
https://www.flickr.com/photos/elettra1143/6900033428/in/photostream/
https://www.flickr.com/photos/elettra1143/6900038410/in/photostream/
https://www.flickr.com/photos/elettra1143/7046133499
And exterior:
https://www.flickr.com/photos/elettra1143/7046128371/in/photostream/

I spotted 13252 on a cross-country service at Bristol TM in the 1980s, I could easily tell that it was 'different' and seeing the number confirmed it was the prototype. One thing that caught my eye was the exterior window frames which seemed to only go around the lower main pane of glass and the last photo in the post above confirms that. On the first production batch of Mk2 FKs the exterior frames went right around the whole window fixture - I can't find a clear picture of any of those online but on page 35 of the Michael Harris book there's a good early photo of 13366 in maroon which shows the exterior frames.

 

[edwin_m]

I spotted 13252 on a cross-country service at Bristol TM in the 1980s, I could easily tell that it was 'different' and seeing the number confirmed it was the prototype. One thing that caught my eye was the exterior window frames which seemed to only go around the lower main pane of glass and the last photo in the post above confirms that. On the first production batch of Mk2 FKs the exterior frames went right around the whole window fixture - I can't find a clear picture of any of those online but on page 35 of the Michael Harris book there's a good early photo of 13366 in maroon which shows the exterior frames.

I think the early Mk2s were the first coaches to be double-glazed, and this might have explained the change to the window frame design.

 

[43096]

MarkIICs were easily distinguishable because they had wrap round end doors.

"Plain vanilla" MarkIIs were distinguishable from MarkIIA and MarkIIB by the absence of air brakes, except for the Scottish push pull vehicles, which were distinguishable in other ways.

Of course it was always possible to cross check the vehicle numbers!

Knowing which sets were air braked and which were vacuum braked was very important operationally.

Mark 2B stock had wrap round end doors as well, did they not?

 

[Merle Haggard]

between the two I think the early Mk2s were the first coaches to be double-glazed, and this might have explained the change to the window frame design.

I am relying on memory, unwise at my age, but weren't some of the Kent Coast Electric (mk1, obvs) sets double glazed when new? Stories of them filling with water between the two panes. And I travelled on the East Lancs in an RMB with double glazing full of condensation, though that might have been a later mod.

 

[Goldfish62]

I am relying on memory, unwise at my age, but weren't some of the Kent Coast Electric (mk1, obvs) sets double glazed when new? Stories of them filling with water between the two panes. And I travelled on the East Lancs in an RMB with double glazing full of condensation, though that might have been a later mod.

I might be wrong, but I'm pretty sure late build Mk1s had double glazing from new.

 

[edwin_m]

I am relying on memory, unwise at my age, but weren't some of the Kent Coast Electric (mk1, obvs) sets double glazed when new? Stories of them filling with water between the two panes. And I travelled on the East Lancs in an RMB with double glazing full of condensation, though that might have been a later mod.

I might be wrong, but I'm pretty sure late build Mk1s had double glazing from new.

That's possible. The window frames changes part way through the Mk1 production run, with later ones having a raised frame whereas it was flush right up to the aperture on the older ones. I have an idea though that this was something to do with corrosion in the original design.

 

[Helvellyn]

9701-10 were the original 10. Disc braked

9711-13 were conversions for extension of push-pull to all Glasgow/Aberdeen services from May 1985. Tread braked

9714 was the replacement for 9706 lost in the Polmont accident in 1984. Disc braked

Did 9711-9713 retain tread brakes when transferred to InterCity? There were certainly surplus Mk 2Zs with disc brakes by then.

 

[Beebman]

I might be wrong, but I'm pretty sure late build Mk1s had double glazing from new.

I can't see any mention of the use of double glazing on Mk1s in Keith Parkin's book (apart from on catering vehicles) but Michael Harris' book on Mk2s does mention its use with late-build Mk1s. Harris has a complete chapter on the prototype coach 13252 and it seems it was fitted double glazing from new but both exterior and interior photos show its seemingly unique style of window frames.

 

[marsker]

I'm fairly sure that the commonwealth bogied Mk 1s on East Coast services in the mid-1960s had double glazed main windows.

On another point within the thread, I remember going on the Waverley Route farewell tour from Newcastle that ran on the final Saturday. That was comprised of an 11 coach Mk 2a set hauled by a Deltic, both much to my surprise. It was steam heated as the loco ran out of water at Hawick on the outward journey, it was really cold by the time we reached Edinburgh.

 

[Sun Chariot]

I remember going on the Waverley Route farewell tour from Newcastle that ran on the final Saturday. That was comprised of an 11 coach Mk 2a set hauled by a Deltic, both much to my surprise. It was steam heated as the loco ran out of water at Hawick on the outward journey, it was really cold by the time we reached Edinburgh.

5-January 1969's "Farewell to the Waverley Route", hauled by D9007 Pinza. Photos on Six Bells Junction (link) give the hint as to that bitterly cold day. The Mk2 stock isn't discernable if the first variant ("z") or 2a.

The Railtour Files

 

[marsker]

The tour from Newcastle was hauled by Deltic 2 as my pictures on the day show:

 

[hexagon789]

5-January 1969's "Farewell to the Waverley Route", hauled by D9007 Pinza. Photos on Six Bells Junction (link) give the hint as to that bitterly cold day. The Mk2 stock isn't discernable if the first variant ("z") or 2a or 2b.

The Railtour Files

The tour from Newcastle was hauled by Deltic 2 as my pictures on the day show:

Mk2As

 

[Sun Chariot]

The tour from Newcastle was hauled by Deltic 2 as my pictures on the day show:

Ah - 9002 KOYLI ran on 4-January 1969's "Waverley" tour.

The Railtour Files

9007 Pinza ran 5-January 1969's tour.

7 5-1-69

At least the Mk2a stock is certain!

 

[Davester50]

That's possible. The window frames changes part way through the Mk1 production run, with later ones having a raised frame whereas it was flush right up to the aperture on the older ones. I have an idea though that this was something to do with corrosion in the original design.

I can remember water sloshing away between the panes on a Mk1 BCK/BFK unusually used on the West Highland line in the mid 1980s.

 

[ge-gn]

Mark 2B stock had wrap round end doors as well, did they not?

Happy to be corrected, but yes I believe 2B stock has wrap around doors, and maintained the middle door, while 2C lost the middle doors. Did 2B also get a toilet either end rather than the two toilets at one end in previous marks?

 

[Goldfish62]

Happy to be corrected, but yes I believe 2B stock has wrap around doors, and maintained the middle door, while 2C lost the middle doors. Did 2B also get a toilet either end rather than the two toilets at one end in previous marks?

I'm sure Mk2B coaches lost the middle door.

Mk2C had passive provision for aircon.

 

[hexagon789]

Happy to be corrected, but yes I believe 2B stock has wrap around doors, and maintained the middle door, while 2C lost the middle doors. Did 2B also get a toilet either end rather than the two toilets at one end in previous marks?

I'm sure Mk2B coaches lost the middle door.

Mk2C had passive provision for aircon.

Wrap-round doors on Mk2B, yes, but no centre cross-vestibule/doors.

Slight length increase over 2Z/A as well to 66ft over body.