Since Coketown was a modern mainline station the signalling needed to be 4 aspect with red, yellow, two yellows and green. I decided that if I made my own signals I had the option of them having working lights or, if I couldn't get the lights to work, make them dummies.
I drew the basic signals using simple shapes in Sketchup which at the time was free. It's now part of Autocad but I still have a copy from 2017 which is about the last free version available. I had the files printed by Shap