Archway

Wasn't it that some area were automated under push button before full automation using programme machines at Cobourg; however *dives into WTT library*...........

Euston reversers stopped in '67, due to the construction works needed for the Victoria line - so (in very simple terms) [1] the Euston reversers transferred to Archway.

Prior to 1967 reversing at Archway was only occasional - and had been thus for the previous twenty years, it could be covered by a push button console - with the extra workload of the former Euston reversers coming into Archway it would need more automation - hence the introduction of the PMs.

From memory the last regular reversing at Archway was during the currency of the winter 1942 timetable; so when automation came along it made sense to automate Archway 'on the cheap' as it were with pushbuttons - so my theory is that if the construction had not taken place at Euston, then Archway might still have been pushbutton to this day!

[1] that's not meant to be patronising - unless you feel that the vagaries of City branch trains below Tooting Broadway (quite rare or non-existent in some TTs) would help!

Euston: 3 machines - bear with me as I'll have to dig out the copy of 'Automatic Junction Working and Route Setting by Programme' as read to the IRSE in 1958ish by Dell: Watford, the automatic engine release at Liverpool St. and Euston were used as worked examples in the presentation.

*starts searching through machine; as I've got it in electronic form somewhere*

I think the installation in the account is edited for dramatic effect , but the general principles are correct for the installation, just some of the details have been simplified.

AIUI Euston had two Sequence Machines: S1 driving the SB, S2 driving the NB and siding. S2 is a double-stepper as it takes into account the reverse/stow/carry on north possiblities.

There was a third PM: a Time Machine which regulated the out-of-turn workings and was the overall control on the appropriate starting signals. The time machine would check time coincidence on S1 and S2.

I can't OTTOMH remember what replaced Time Machines - was it just a time coincidence relay set or electronic cards or modula design?


EDIT:

AIUI the SB train descriptions at Archway are set up manually and the time coincidence is done electronically - there is no double stepping here as there had been at Euston.

I suggest that the original installation at Euston used the Time Machine to drive the sequence machines and set up descriptions - when Archway was commissioned time machines were seen as superfluous and replacement electronic or relay units were used.

Perhaps the block diagram below would help?




The modified numbering used at Euston for the technical paper is:



which is different to the 'original' (see what I mean about it being edited for 'dramatic effect') - I think I've got diagrams of the 1926 and 1938 installations somewhere.

time machines (T1) were replaced by time coincidence units they are a pig to set up correctly and are usually set 1 - 1 1/2 mins fast. the time coincidence units are a piece of cake to set up though

actual time