Is there a shower on the train to Tibet

No, there is no shower on the train to Tibet. You will have to wait to arrive in Lhasa for the shower.

We like to urge all travellers to take a shower in the hotel or the hostel at your departure city. So that you will be ok during your Journey to Lhasa.

https://itibettravel.com/faq-items/is-there-a-shower-on-the-train/