There is no changes in rules, because the carrier is the same - RZD.
About the dog transit rules:
You must have all medical information about pet, and you must pay for additional ticket. Also you must honor the sanitary rules in the train you are using.
There are two options for this transit - and it depends on size of the dog.
For small dogs the rules are very simple - you put it in the special container and it counts as your luggage and you can borrow it to 1st class and 2nd class (you cannot book sleeping wagons and business class trains).
For big dogs the situation is more about the money you will spend for the transit:
Options you have:
- Special not-in-use box in the first wagon of the train.
- Fully-paid room (4 tickets) in 1st class (you cannot book sleeping wagons and business class trains).
Link in Russian
The only link in English about transporting animals in trains (not very applicable for the Trans-Siberian, but better than nothing):
- Passengers may transport pets if such transportation is not prohibited by vets, customs or other regulations of the Russian Federation and the Republic of Finland.
- Passengers may take no more than two dogs on a leash or not more than two cages or one dog on a leash and one cage. Cages must be 60x45x25 cm maximum. Several animals may be taken in one cage.
- Animals must not be placed in carriage aisles or vestibules.
- Passengers travelling with pets are responsible for their animal(s) and for any inconvenience or damage caused by animals.
- Animals are prohibited in first class carriages