Post by jimbo on Jan 15, 2024 11:19:04 GMT
As the arrival of the first articulated train on the Picc draws close, can we clarify what went wrong with plans for articulated trains there some 50 years back? After the original Victoria Line fleet was delivered, it seemed that the Northern Line was due for the next fleet replacement. There was talk of articulated trains of 1972 stock, but following approval of a Picc line extension to Heathrow, that line took precedence, with its smaller fleet of 1959 stock transferring to the Northern Line. The difference was made up with two batches of the Victoria Line style of train, then called 1972 stock. The new envisaged fleet was running late, and now took the label 1973 stock. I recall an artist's impression of the open articulated car ends. A trial on two 1935 stock motor cars cut away the end single doors, with a shared bogie beneath. This could be seen at Acton Works where it was a useful shunter, easily bridging current rail gaps.
The build of trains with splitable units continued throughout the century, so it is unlikely that a complete walk-though train was envisaged in those days. The trial articulated cars were, of course, shorter than their original formation. Does this mean that a seven-car 1959 stock train would have been replaced by an eight-car articulated formation? Was this to be formed of four articulated pairs of cars with conventional inter-car connections at their outer ends? This would have given a train with a dozen bogies, perhaps eight powered and four unpowered under the articulations. Or was the trial just to demonstrate the articulated connection, and the actual trains could have been two four- or five-car units with the new car-end throughout each unit.
I believe there was a problem providing a reasonable sized walkway with sufficient strength, given materials of the time. Studies of maximum permissible car lengths must have revealed that a 6-car conventional train, also with a dozen bogies, could provide similar capacity, providing the 1973 tube stock that we know today, together with similar trains up to the 1996 tube stock. These also have eight powered and four unpowered bogies.
The idea of articulated tube trains returned with the planned renewal of the Victoria Line fleet, with the Space Train, but this was lost with PPP encouraging the Infracos to use conventional technology. So it was only with return of control to LU that the idea could be revisited with the first fleet replacement since PPP, a half-century after the original Piccadilly Line experiment, and 25 years since the Space Train concept. Things can take time!
The build of trains with splitable units continued throughout the century, so it is unlikely that a complete walk-though train was envisaged in those days. The trial articulated cars were, of course, shorter than their original formation. Does this mean that a seven-car 1959 stock train would have been replaced by an eight-car articulated formation? Was this to be formed of four articulated pairs of cars with conventional inter-car connections at their outer ends? This would have given a train with a dozen bogies, perhaps eight powered and four unpowered under the articulations. Or was the trial just to demonstrate the articulated connection, and the actual trains could have been two four- or five-car units with the new car-end throughout each unit.
I believe there was a problem providing a reasonable sized walkway with sufficient strength, given materials of the time. Studies of maximum permissible car lengths must have revealed that a 6-car conventional train, also with a dozen bogies, could provide similar capacity, providing the 1973 tube stock that we know today, together with similar trains up to the 1996 tube stock. These also have eight powered and four unpowered bogies.
The idea of articulated tube trains returned with the planned renewal of the Victoria Line fleet, with the Space Train, but this was lost with PPP encouraging the Infracos to use conventional technology. So it was only with return of control to LU that the idea could be revisited with the first fleet replacement since PPP, a half-century after the original Piccadilly Line experiment, and 25 years since the Space Train concept. Things can take time!
