To add to the comments a great piece of art and hopefully you are proud of it - I know I would be ! Certainly catches the urban feel to a "T" and I am sure the boys at IRM like the ballast and bubbles ...
Certainly watch in awe and with interest.
Thanks DV, that's interesting. I've seen that video clip before but wasn't sure how reliable it might have been due to wear or chaffing on the fine thread. Do you know if it still working well for your friend on the BR 2-6-4T loco?
I hadn't seen that type before. Below is a link showing the type I fitted. The servo can be fitted anywhere as long as it is 90 degrees to the coupler. It operates by pulling on a length of fine thread.