Transport of sidecar Moskou to Novosibirsk with train
 

We are planning a bike trip from the Netherlands to Mongolia this summer and we are still looking for a transport for our motorcycle with sidecar from Moskou to Novosibirsk. (we drive to Moskou and then drive from Novosibirsk to Mongolia)
We know about the Trans siberian express, but because our motorcycle has the sidecar on it, it wouldn't fit through the doors that we have seen on the pictures we could find and we heard from another traveler with a sidecar that the doors wouldn't be wide enough. We would tipically need the width to be about 1.9 meters.
Does anybody know if there is a way to transport our motorcycle with sidecar from Moskou to Novosibirsk? Any help is welcome.