Single lead Junctions

The Up line on the ECML north out of York, used by Harrogate bound trains. Quite unnerving rare moment when you have just completed the turn outs and a ICE come cruising south.

Another factor in past-versus-present layout decisions would be that with mechanical signalling, quite often every switch needed a separate lever (and another for each facing point lock). This adds cost and size to the interlocking, and increases the workload (and time) for a signaller operating a 'ladder' junction versus one with fixed diamonds.

Power signalling allows multiple switches to be moved and locked simultaneously, so that's doubtless one factor in the popularity of ladder junctions these days.

yorkie said:

Actually, I think the answer is probably down to cost: there has to be such a crossover northwest of the station for the Milgavie branch... so they avoid duplication by not having a rarely used set of points to be maintained.

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Both the Milngavie junction and the Maryhill branch junctions used to be conventional double junctions (although the down Maryhill branch had spring points, normal position open to the branch). The crossover at the Milngavie junction was a trailing one, not a facing one.

I'm not sure about the date of change, but it may have been as a result of the Yoker IECC resignalling.

matchmaker said:

Both the Milngavie junction and the Maryhill branch junctions used to be conventional double junctions (although the down Maryhill branch had spring points, normal position open to the branch).

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Latterly though, all the points were motor-operated.