7-car 1992 tube stock for the Bakerloo Line?

[jimbo]

Operation of a 7-car formation of 1992 tube stock on the Bakerloo Line was suggested in another thread. I wonder if this could be economical and practical?

It could be better to delay an order for new Bakerloo trains until the Lewisham, and beyond, extensions are clearer, when the economic case for resignalling and new trains would be stronger. Ordering 41 trains now, and perhaps later another 37 for Hayes or 9 for Lewisham, would require a second build to match the first. And yet the need to replace the current fleet remains urgent, due to poor reliability and high maintenance costs.

In the meantime the Central line case for new trains is stronger with a need for higher capacity, assuming a return to pre-Covid demand at some time. This could allow the release of 41 trains to the Bakerloo to cover the service planned there with a new fleet. The car lengths are similar to current Bakerloo trains, leaving a similar gap at curved platforms to now.

However, a car would need to be trimmed from each Central Line train, perhaps easiest by splitting 21 2-car units and making them trailer cars to insert into the remaining middle unit to provide a 7-car formation. When an extra car was inserted into some R stock formations, the electrical burden was shared between the cars either side. They may require a boost to compressor capacity. The cost of such modifications could be spread over a service life of perhaps 50 or more years in total, helped by the current CLIP modifications. These trains were manually driven for nearly a decade, when first introduced. They may need a cab CCTV link if the current monitors are unsuitable. The depot would need updating to maintain the new fleet.

[Tom]

The work to modify the trains might be prohibitive - fitting standard Correct Side Door Enable equipment, fitting a more permanent tripcock, etc just off the top of my head, but there are probably other alterations required.

If the Bakerloo passenger numbers are lower, then perhaps a six car formation rather than seven?

[Chris L]

Feb 4, 2022 21:04:18 GMT jimbo said:

Operation of a 7-car formation of 1992 tube stock on the Bakerloo Line was suggested in another thread. I wonder if this could be economical and practical?

It could be better to delay an order for new Bakerloo trains until the Lewisham, and beyond, extensions are clearer, when the economic case for resignalling and new trains would be stronger. Ordering 41 trains now, and perhaps later another 37 for Hayes or 9 for Lewisham, would require a second build to match the first. And yet the need to replace the current fleet remains urgent, due to poor reliability and high maintenance costs.

In the meantime the Central line case for new trains is stronger with a need for higher capacity, assuming a return to pre-Covid demand at some time. This could allow the release of 41 trains to the Bakerloo to cover the service planned there with a new fleet. The car lengths are similar to current Bakerloo trains, leaving a similar gap at curved platforms to now.

However, a car would need to be trimmed from each Central Line train, perhaps easiest by splitting 21 2-car units and making them trailer cars to insert into the remaining middle unit to provide a 7-car formation. When an extra car was inserted into some R stock formations, the electrical burden was shared between the cars either side. They may require a boost to compressor capacity. The cost of such modifications could be spread over a service life of perhaps 50 or more years in total, helped by the current CLIP modifications. These trains were manually driven for nearly a decade, when first introduced. They may need a cab CCTV link if the current monitors are unsuitable. The depot would need updating to maintain the new fleet.

1992 stock was a disaster from the start. Wouldn't wish it on anybody.

I'd be amazed if they avoid scrapping before too long.

[johnlinford]

Feb 4, 2022 21:04:18 GMT jimbo said:

In the meantime the Central line case for new trains is stronger with a need for higher capacity, assuming a return to pre-Covid demand at some time.

Won't the Elizabeth Line reduce pressure on the Central though?

[metman]

Trains were a great deal more simple when the R stock was converted to 7 cars (4+3 or 3+2+2) so I’d agree with Tom about the cost implications. I’m not sure 6 car trains would be permitted as an upgrade though.

I don’t know that much about the 1992 stock, so I don’t know what capacity the NDMs (B cars) have to have modifications to make them into a three car unit with an A or C car?

The 1992 stock certainly hasn’t been successful so or popular so the proposal may be a non starter.

[100andthirty]

Feb 4, 2022 21:42:57 GMT Tom said:

The work to modify the trains might be prohibitive - fitting standard Correct Side Door Enable equipment, fitting a more permanent tripcock, etc just off the top of my head, but there are probably other alterations required.

If the Bakerloo passenger numbers are lower, then perhaps a six car formation rather than seven?

The are designs available for the modifications Tom mentions as these systems are fitted to the W&C cars. Buth they're just the tip of a rather large iceberg. 1992 tube stock was designed based around 2-car units and most of the expensive systems (traction equipment auxiliary converter, compressor) are distributed across the two cars in each unit. So just using one of them leads to lots of modification. Even the notion of converting a car into a trailer car to be inserted in a B-C unit is far from trivial. There is nothing extant to control just the friction brakes on a trailer car. None of the suspension is set up to support a trailer car and it might well need to be ballasted to maintain the weight.

Then there's the issue of steps and gaps at the curved platforms. 1972 tube stock has sills that extend slightly from the bodyside. 1992 tube stock doesn't have these. Thus all 1992 tube stock steps/gaps will be about 50mm worse than on 1972 tube stock.

[spsmiler]

Six car trains formed of DM + T wonr need so much modification

That said, despite being a few decades younger I suspect that the 1992ts is just as knackered as the 1972ts!!!

[Chris M]

The 1992 stock suffers from build quality being noticeably lower than the design quality. It also suffers from being designed and built at the very start of the computerisation revolution at a time when the technology was moving very rapidly, meaning replacement parts are not as easy to come by as for either older or newer stock.
Separately, I believe the lack of visual information means the stock is non-compliant with current regulations. Obviously it's use on the Central line is grandfathered in, but don't know that that would automatically transfer to a new line. If it doesn't then a derogation would have to be applied for with no guarantee it would be granted. If 1972s are retrofitted with visual information then it's pretty much guaranteed that this would need to be done also on the 1992s, but I have memories of reading somewhere (most likely on this forum) that this has been investigated and found to be complicated and/or expensive.

These factors, combined with what others have said, makes me think that if a fleet of trains is going to be cascaded it wont be the 1992s.

[Dstock7080]

Feb 5, 2022 23:51:59 GMT Chris M said:

Separately, I believe the lack of visual information means the stock is non-compliant with current regulations. Obviously it's use on the Central line is grandfathered in, but don't know that that would automatically transfer to a new line. If it doesn't then a derogation would have to be applied for with no guarantee it would be granted. If 1972s are retrofitted with visual information then it's pretty much guaranteed that this would need to be done also on the 1992s, but I have memories of reading somewhere (most likely on this forum) that this has been investigated and found to be complicated and/or expensive.

These factors, combined with what others have said, makes me think that if a fleet of trains is going to be cascaded it wont be the 1992s.

1992s are having wheelchair spaces and visual displays fitted as part of the ongoing CLIP

[metman]

Feb 5, 2022 17:54:42 GMT 100andthirty said:

Feb 4, 2022 21:42:57 GMT Tom said:

The work to modify the trains might be prohibitive - fitting standard Correct Side Door Enable equipment, fitting a more permanent tripcock, etc just off the top of my head, but there are probably other alterations required.

If the Bakerloo passenger numbers are lower, then perhaps a six car formation rather than seven?

The are designs available for the modifications Tom mentions as these systems are fitted to the W&C cars. Buth they're just the tip of a rather large iceberg. 1992 tube stock was designed based around 2-car units and most of the expensive systems (traction equipment auxiliary converter, compressor) are distributed across the two cars in each unit. So just using one of them leads to lots of modification. Even the notion of converting a car into a trailer car to be inserted in a B-C unit is far from trivial. There is nothing extant to control just the friction brakes on a trailer car. None of the suspension is set up to support a trailer car and it might well need to be ballasted to maintain the weight.

Then there's the issue of steps and gaps at the curved platforms. 1972 tube stock has sills that extend slightly from the bodyside. 1992 tube stock doesn't have these. Thus all 1992 tube stock steps/gaps will be about 50mm worse than on 1972 tube stock.

Interesting. I hadn’t considered the door sills being an issue too. Thanks.

[t697]

ISTR the Brake Decoder is the 'master' on these cars, so maybe not so difficult in that respect to arrange it as a brake own weight with friction brake only car.
The door sills and stepping distances is a significant issue though. I'm sure it wouldn't be acceptable to make the gaps worse unless there was a very strong case of economic necessity if 'managed decline' becomes a fixed policy. In that case, degrading the service to 6 car trains of same car lengths as the 72TS might be a thing too. Oh dear...

[jimbo]

Thanks for the many insights above. I had the following thoughts in response:

It was planned to get 42 new trains for the Bakerloo, later 41 to cut cost of new fleet, but 42 second-hand trains of 6-car operation would match service with current 36 x 7-car trains (both 252 cars). 1992ts has higher standing capacity, so only 8% increase in 6-car trains would match current 7-car fleet, or 39 trains, with 42 x 6-car trains providing a capacity uplift. If a 7-car version of 1992ts could be operated, it would provide 8% additional capacity on current Bakerloo trains with only 36 trains transferred.

The current Bakerloo trains were intended for eventual auto-operation so probably have removable tripcocks as 1967ts had on the Victoria Line, and perhaps could then fit the replacement 1992ts as they arrive on the line.

Central Line demand was expected to soon bounce back after Elizabeth Line opening, especially building from the Ruislip and Epping branches.

The CLIP project is expected to greatly improve operation of 1992ts with new motors and computers in a £525m. programme including CCTV, passenger information systems, LED lighting, wheelchair bays, new seats, etc.

Of course, this would all depend on funds becoming available later in the decade for a new fleet for the Central Line and for adaption of the Bakerloo Line/1992ts to suit.

[Chris L]

Feb 9, 2022 19:48:59 GMT jimbo said:

Thanks for the many insights above. I had the following thoughts in response:

It was planned to get 42 new trains for the Bakerloo, later 41 to cut cost of new fleet, but 42 second-hand trains of 6-car operation would match service with current 36 x 7-car trains (both 252 cars). 1992ts has higher standing capacity, so only 8% increase in 6-car trains would match current 7-car fleet, or 39 trains, with 42 x 6-car trains providing a capacity uplift. If a 7-car version of 1992ts could be operated, it would provide 8% additional capacity on current Bakerloo trains with only 36 trains transferred.

The current Bakerloo trains were intended for eventual auto-operation so probably have removable tripcocks as 1967ts had on the Victoria Line, and perhaps could then fit the replacement 1992ts as they arrive on the line.

Central Line demand was expected to soon bounce back after Elizabeth Line opening, especially building from the Ruislip and Epping branches.

The CLIP project is expected to greatly improve operation of 1992ts with new motors and computers in a £525m. programme including CCTV, passenger information systems, LED lighting, wheelchair bays, new seats, etc.

Of course, this would all depend on funds becoming available later in the decade for a new fleet for the Central Line and for adaption of the Bakerloo Line/1992ts to suit.

I fear you are trying to flog a dead horse. The trains were assembled from various suppliers. The Kawasaki bogies had to be welded together soon after delivery which invalidated the warranty. The oversize windows meant that the bodies flexed.

The current life extension work is a short term fix.

[100andthirty]

ChrisL. Bogies were originally from Kawasaki. They were replaced just over 10 years ago with bogie frames by Siemens. The latter have been trouble free.

[Chris L]

Feb 10, 2022 6:39:36 GMT 100andthirty said:

ChrisL. Bogies were originally from Kawasaki. They were replaced just over 10 years ago with bogie frames by Siemens. The latter have been trouble free.

Corrected. The points I was making were about how bad they were when new.