The lethality of the war is at a very potent stage this month all over Europe. Train travel is very dangerous as many train stations are simply being blown up in Europe now.
UK intel says however Russia themselves are unlikely to protect their own network of rail and train:
https://www.pravda.com.ua/eng/news/2023/05/5/7400773/
Indeed.
Putin of Russia likes to travel by train and this will be problematic for him in due course surely.