Summary

Here's a file for a fire escape or external stairs drawn full size so scale to suit your needs. it's quite delicate and I recommend printing in ABS like resin. I printed the examples in 1/76 on an Elegoo Mars 2 resin printer, it just fits in the build area.

The photos are of finished models in situ on Greg Brook's Shenston Road and Kier Hardy's Hornsey Broadway model railways.

Enjoy