You will have to depend on both yourself and strangers you meet. If you can't detect my bias, I'll tell you that it's for independent travel. However, I wouldn't recommend it unless you are sure that's it's for you. There are plenty of drawbacks and even hazzards to this type of travel. There's no shame, and maybe a bit a prudence, in letting others do some of the work for you.
Independent travel can be risky.
But as with most any endeavour, return is proportionate to risk. The Train Train life is what you want to make of it. If you want to sit and do nothing, there will be up to seven days of as doing as little as you want. You also have the option of reading yourself blind, writing, conversing with any number of people, eating all you want, watching the scenery slip by, or the Russian favorite, drinking youself to a stupor on undiluted vodka. Attire on the Trans-Siberian is definitely informal.