From my notebook...
...dimensions and cutting notes (on the small lathe) for signal lamps, based on GWR drawings reproduced in Adrian Vaughan's 'Great Western Signalling". The lamps are bored out 3mm to house a 3mm water clear LED. Although not common, I sourced some flangeless LEDs (Toby Electronics - Toby.co.uk) which will fit right into the lamp case, leaving only the clear base of the LED to be painted and stop light spillage. The lamp is cross drilled to take the front and rear lenses which are thick walled brass tube, turned down at the ends to fit the cross drilled holes in the casing - then soldered in, filed to length and cleaned up.
The lamp cases are Birchwood blacked and glazed with Glue'n Glaze. I forgot to put a kerf to house the wiring into one of the signal dolls so the wires run up the face of the doll but in all other cases, a pair of 0.02mm wires are set into the posts and dolls (www.componentshop.co.uk for the wire). The same cases are used on the buffer stops but with flangeless red LEDs.
The lamps are powered by an ex mobile phone USB charger via a set of circuits incorporating a fixed resistor sized to suit the number of LEDs on each circuit and also a variable resistor to control brightness.
I've made fork end connectors for the signals - the Up starters use a "compensation" beam and really need an engineered connection which is to say that I've never had much success putting a small bend on each end of a length of piano wire and getting it the right length - the advantage of the fork end is a small measure of adjustability - the pictures show how that's possible.
The same fork end detail is used for the point rodding, but smaller - 2.75mm long x 1.2mm square with a 0.7mm diam pin onto the cranks. The pins are about 1mm long and I dare say there are a good few spread round the workshop - missing in action. The pictures show one set of rods/cranks, recently installed and waiting on Birchwood metal black. The dimension between rods (centre to centre) is setup by the ModelU rod guides - where there is a 90 degree turn, the cranks need to be set very close together using the GWR type curved/straight cranks set at different levels. The point rodding "works" although it's the point servos moving the cranks and not a set of levers in a signal box - some runs aren't connected to anything but there's enough that are to create the illusion.