How long did Sykes' Lock and Block last?

[Rescars]

I read recently that the Sykes' Lock and Block electro-mechanical installation at Battersea Park, which had been installed during the Edwardian period, was well worn with slack in the mechanism at the time of the accident there in 1937 and the installation at South Croydon would have been replaced well before the accident there in 1947 had not WW2 intervened. All this suggests that Sykes' Lock and Block had done its stuff, but was getting past its "sell-by" date by the time of nationalisation. Yet the Southern's Signalmen's Additional General Instructions dated 1960 included full working instructions for various types of Sykes' Lock and Block instruments, which suggests they remained in use in some locations almost until the end of the steam era. Does anyone know when and where the last Lock and Block installations were decommissioned on the Southern, or indeed anywhere else on the network?

 

[Gloster]

A skim through the Signalling Record Society’s Signal Box Register from 2009 suggests that there was quite a lot of it about until 1970 or 1971 particularly in South-East London and north-east Kent, after which there was a further decline in the middle of the decade. Otford Junction-Sevenoaks seems to have lasted until 1981, while Coulsdon North-Redhill No. 2 appears to have lasted until February 1983.

N.b. This is only a quick survey and I haven’t double-checked the above.

 

[4069]

All of the South Western suburban lines which came under Feltham panel around 1973 were worked by Sykes up until then.

 

[Gloster]

All of the South Western suburban lines which came under Feltham panel around 1973 were worked by Sykes up until then.

According to the Register they were a mix of Sykes’ Lock & Block, Preece 3-wire (possibly also 1-wire) and SR 3-position, with a bit of TCB around Barnes and Richmond. Again, based on a quick look.

 

[Rescars]

According to the Register they were a mix of Sykes’ Lock & Block, Preece 3-wire (possibly also 1-wire) and SR 3-position, with a bit of TCB around Barnes and Richmond. Again, based on a quick look.

The survival of such a variety of different systems in a relatively small geographical area does seem remarkable, especially since presumably most of the original installations would have been commissioned by the LSWR. Preece 1-wire does seem a bit primitive compared with the others.

Coulsdon North-Redhill No. 2 appears to have lasted until February 1983.

This survival on the Brighton Main Line into the 1980s seems even more remarkable. At the time of the accident, Battersea Park was the last box out of Victoria to operate full Lock and Block. Apparently conventional 3-position working started at the next box south, Pouparts Junction. If these arrangements were deemed appropriate this close to Victoria, I wonder where Lock and Block commenced again (Selhurst perhaps?) and why it was considered necessary as far south as Coulsdon (Stoats Nest) and Redhill. Did it stretch further south at some stage, at least as far as Three Bridges perhaps?

 

[Gloster]

The survival of such a variety of different systems in a relatively small geographical area does seem remarkable, especially since presumably most of the original installations would have been commissioned by the LSWR. Preece 1-wire does seem a bit primitive compared with the others.

The 1-wire line was Strawberry Hill Junction to Shepperton, which had it from doubling around 1878 to 1974. It was suspended 1940 to 1946 and replaced by Electric Train Token while Single Line Working was in force.

This survival on the Brighton Main Line into the 1980s seems even more remarkable. At the time of the accident, Battersea Park was the last box out of Victoria to operate full Lock and Block. Apparently conventional 3-position working started at the next box south, Pouparts Junction. If these arrangements were deemed appropriate this close to Victoria, I wonder where Lock and Block commenced again (Selhurst perhaps?) and why it was considered necessary as far south as Coulsdon (Stoats Nest) and Redhill. Did it stretch further south at some stage, at least as far as Three Bridges perhaps?

The main line through to Brighton via the Quarry Line south of Coulsdon was converted from Lock & Block to Track Circuit Block by 1932 and north of there by the mid-1950s: as you say, this was probably delayed by the war. Although Coulsdon-Redhill was only a six-mile section, I suspect it was not seen as part of the main-line and so a priority.