I have updated my Omnibus. It has bigger wheels and finally the hand-railing is there, too. Originally I wanted to use the castle wheel on this MOC but I could not come up with a good tyre solution so I used smaller wheels instead. Some time ago a friend of mine pointed out the wedge-belt tyre on this MOC. So I only had to steal it. Actually, this is a very tight fit, it is not easy to put that belt on the wheel.
Also, I haven't linked the original vehicle that inspired me to build my MOC: MARTA 1909