We took the Trans-Mongolian from Moscow to Beijing. Hopefully some of this practical detail will help anyone thinking of taking the plunge.
Overall the journey is a bit like attending a music festival without the music. If you've ever been to festivals or done lots of camping you will be fine. Do not expect luxury. We weren’t bored for a single moment. Watching the world go by and chatting to family & fellow travellers was endlessly interesting.
Buffet cars are not 24hr, and are often expensive. Food/drink on platforms is very cheap. We found it difficult to buy alcohol from platform sellers, it maybe illegal for them to sell it. Some larger stations stock beer.
We took our 10yr old son. He struggled a bit but like us he settled into the dreamy train life after a day or so. There were quite a few other children travelling and provided they have entertainment with them there should be no problem. We took a tablet, pens/paper, playing cards, books, and a travel journal for him to record his experiences.
The time zones freaked us out a little. It wasn't until we were fairly close to Irkutsk that we realised we'd been living on Moscow time for four days and needed to adjust.
Moscow - Irkutsk
We didn't get tickets for the best train (#002) despite booking with a tour company many months ahead. Train #070 turned out to be ok but got hot and smelly when at a standstill. Staff were professional, restaurant food very average. Wine/beer was good but expensive. Our second class carriage had two working power points. We bought Russian SIM cards from the phone shop in Domodedovo Airport (departures, second floor). Very helpful staff here who recommended Yota SIMs that worked all the way to Mongolia. There is 3G coverage near towns & cities only.
Irkutsk – Ulan Bataar
Train #362. Still basic but a step up since it didn’t stink. There was no power in second class cabins so several sockets in the corridor were in high demand. Sadly the provodnista on this train treated her passengers like vermin: we were shouted at, forcibly pushed in the corridors and made to feel like barriers to her obsessive cleaning schedule. Excellent restaurant car – people having fun, pleasant staff. We did not eat but the food looked good.
Ulan Bataar – Beijing
Train #024. Second class carriages were plush, staff were fantastic. One power socket in cabin. Separate sinks at the end of the carriage for cleaning cups/bowls and for cleaning human bodies - very civilised! Restaurant car was dirty and sad, the menu was hand written on a notepad. We stuck with our own food supplies.
Essentials for the journey: food, local currency, anti-bacterial gel, toilet paper, wet wipes, kitchen roll, penknife, sandals/slippers, USB power pack.