Not sure if I haven't already done so, but I'll throw another option out there to book train tickets in China.
I'd call this an option that was very useful for non-Chinese speakers in the past, because it was likely the easiest and most English-friendly way to book train tickets.
Not 100% sure of its usefulness nowadays, but apparently it's still going.

App is available on the Play Store, called China Train Booking, logo looks like this:




I've used them several times in the past and their customer service was excellent at that time. I'm sure they have a [hefty?] surcharge, so keep that in mind.
Might still be a good option for the inexperienced tourist.