3-aspect signal at Liverpool Street SSL

Close, but no cigar.

OD2 is indeed an old head, and originally had an 'S' light in the lowest lens.

S lights were 'starting lights', operated by the guard touching a low-voltage catenary on the platform and completing a circuit.

Some, but not all had train starting bells worked off the same circuit.

Bear with me and I'll have a rummage around for pictures.

Linky is the old style train starting bell, where the guard would pull on a string and make the circuit. Linky this is the 'new' style with the guard making contact with the brass ferrule on the end of his flagstick, linky this is a better view.

I've got a bit written somewhere about the S lights too.....

These signals are BPRS (British Power Railway Signal Co) and date from the 1932/3 resignalling when this bit of the Circle and Widened Lines was brought up to the same standard as the 'extension railway', some locations used a separate 'S' light (you can still, I think, see the hole in the post on OH 28 Farringdon WB starter) where a separate 'S' unit was fitted, like the 'A' lights for automatic working, the starter in the other direction A 249? is of the same format.

Possibly - *rummage*

The "eastbound" station starter at Ickenham MUX743 (the Met doesn't become 'southbound' until Rayners Lane substation gap) is a relic from Metropolitan Railway days when they had three-aspect signalling, on that branch until 1948.

There are several of these signal heads still around, and on the Uxbridge branch are:

A723 West Harrow southbound home
A727 Eastcote – Rayners Lane eastbound intermediate
A728 Eastcote westbound station starter
MUX743 Ickenham eastbound station starter
R744 Repeater for Hillingdon westbound home signal
MW4 Uxbridge eastbound advanced starter

Those on the Stanmore branch will probably go when the new signalling is commissioned - whenever that might be!

There are some on the Watford branch, the Hammersmith & City, but between Harrow and Finchley Road, only two survive -

A552 Preston Road northbound ‘local’ advance starter
MD1 Finchley Road southbound Metropolitan outer home

There are also a few of these signals that have infiltrated non Met Railway lines, such as (list not complete) -

R491 – Repeater for Kilburn Park southbound home (by QP south shed)
WV2 – South Harrow westbound inner home signal (with junction route indicator)
A580 Westbound ‘local’ intermediate Stamford Brook – Turnham Green

Please don't tell me that's your scooter on the right!

Shame they can use that platform anymore....