I see that in order to buy a train ticket from Delhi to Agra, I need to input an Indian mobile phone number. I'm from the US, and I don't have said number.

I read that one can send a copy of their passport via email to India Rail, and they will email me an identification number to validate my account. I emailed my passport photo page several days ago, and I haven't received a reply.

Any other suggestions? Is there a reputable online travel agent from whom I can buy my tickets in advance from the US? Surely, I can't be the first person to have difficulties.

Should I buy the tickets before coming to India? (And how?) We want to make sure to have seats in an air conditioned train car from Delhi to Agra and then the return.