1972 Mk.I / Mk.II vs. 1983 Batch 1/ Batch 2

[jimbo]

The post-war build of 1938 stock was classified 1949 stock. The Central Line build of Piccadilly 1959 stock became the 1962 stock. I wonder why the two builds of 1972 stock were labelled Mark I and Mark II. The 1973 stock was originally called 1972 stock during its development, but re-labelled as 1973 stock when it became obvious that it was running late. So when an unexpected order for a different train was placed under political pressure, it could take the 1972 stock label. However, when an originally incompatible second build was placed under similar pressure, there was no spare year left, so it was also 1972 stock with Mark I and Mark II to differentiate between them. A pity it could not have become 1973 stock, with that slipping further to 1975 stock, when it actually arrived, but perhaps no further slippage could be politically recognised.

How come the second order of 1983 stock was not 1987 stock, when it arrived after the 1986 prototypes, or even Mark II following precedent, but rather Batch 2, despite being compatible?

If a further build of new trains for the Bakerloo is eventually approved, given they will feature steerable bogies and perhaps other changes based on Piccadilly line experience, will they still be 2024 stock? Or Batch 2 or Mark II, or perhaps 2027 stock? Any bets?

There seems to have been more types recognised with surface stock, e.g. Q23/27/31/35/38, R38/47/49/59, A60/62, and C69/77.

[t697]

I seem to remember that at the time, we called the second batch of 83TS as 1983TS Mk2 (rather than with 1972 TS Mark II). Not sure why really. There were fewer significant differences between the two batches than with 1972TS though and the control schemes were identical I recall. Many of the mods from Mk1s were included from new of course and the bogies had the weakness addressed by design change although they were interchangeable and the differences not visible once under the carbody.

72 Mark II had some metrication compared to Mark I, different weak field settings, top hung doors, different interior decor, 'provision for ATC', several more minor equipment tweaks and no doubt other differences I've forgotten. Of course over the years the two types were modified differently with Mark II's going OPO and many other differences. A few Mark I cars have later been modified to augment the Mark II feet with the rest scrapped of course.

[t697]

Is that point about steerable bogies for a second batch of 24TS type trains a definite?

[jimbo]

Well, a second batch isn't at all definite! Steerable bogies have always been the ambition for NTfL, but were left out of specification for the first build as less important for the Picc Line layout. Bakerloo and Central Line have been intended to include them, but I'm not sure how much work has been done so far.

[brigham]

Steerable bogies are like monorails.

Best left to amusement park rides!

[metman]

Steerable bogies were tried on a 1972 stock car I believe but was not reliable enough for further inclusion.

There were also two batches of 1967 stock too but I don’t think they were officially labelled or recognised as such?

For me the main difference between the 1972 and 1983 stock batches which has been eluded to, was that the 1972 batches were not compatible at first, whereas the 1983 stock batches were.

If any further batches of new tube stock was built it will be interesting to see what the differences are.

[jimbo]

Aug 10, 2022 18:26:27 GMT metman said:

..... There were also two batches of 1967 stock too but I don’t think they were officially labelled or recognised as such? .....

What differences? Do you mean there were two batches ordered, the initial main order plus a second for the Brixton extension? I thought there was one production run which provided all trains well before the Brixton extension was completed. There was an additional order for 1962 stock to cover the Aldwych branch and 1960 stock trials, but they were all one production run.

[bigvern]

As regards the 1967ts there was a variation with the Brixton batch which had AEI Motor alternators and the first batch had English Electric.
The EE alternators were more unreliable, as if they overspeeded due to a regulator fault would cause the cab light bulb to explode in some cases and the Motor Alternator to run at a very high speed like a jet engine.

[towerman]

The original build for 67TS was 3001 to 3061.3062 to 3079 were ordered when the Brixton extension was given the go ahead,there was no break in delivery.3001 to 3051 were fitted with EE motor alternators,3052 to 3079 were fitted with AEI motor alternators.The commutator brushes on th EE machines were quite small and wore down quickly making them prone to flashovers.

[t697]

And if I recall correctly, the EE motor alternators and their associated equipment were changed out for the AEI type, salvaged from 1962TS when those were scrapped.

[jimbo]

Aug 8, 2022 19:24:56 GMT jimbo said:

..... If a further build of new trains for the Bakerloo is eventually approved, given they will feature steerable bogies and perhaps other changes based on Piccadilly line experience, will they still be 2024 stock? Or Batch 2 or Mark II, or perhaps 2027 stock? Any bets? .....

Internal TfL documents now refer to the proposed new Bakerloo Line 9-car trains as 24TS, the same as the Piccadilly Line fleet. The build will feature line-specific seating moquette, and choice of flooring and grab-pole colours. There is no mention of the earlier planned steerable bogies for this line, but train equipment modification may be necessary to meet Network Rail requirements. They could have called it 28TS, that's if the money comes through! Perhaps it will get its own grouping when the delivery year is finally clear?