Not sure about train but can read richard barrows Asian Train Guide to find out. But e visa is easy enough just make sure you are on correct page. Saves a page in your passport
Pops up every now and then as still to discuss. Saw news last week discussing with Cambodian goverment. But its been talked about on and off for years and nothing happens
Yes mine helped me out during covid. Was proof of residency and i was stuck in Singapore and embassy there got three of us farangs in on a repatriation flight because we had these and yellow book. So for me was worth quite a lot more than a pinch of salt.