What class of travel is suitable for a woman travelling alone on Indian railways?

As an Indian and a woman who has travelled a lot on Indian trains, I must tell you that train travel in India, even for solo women travellers, is largely safe. Sure, there are reported instances of theft, harassment - but where do you not hear them?

My advice: travel either by 2 tier or 3 tier A/C coaches. In sleeper or non-A/C classes, especially in North India, you may travel with people unused to seeing foreigners, so you may get a lot of stares and questions. As far as I know women-only compartments are available only in general class and sleeper class. If I were you, I would avoid these. The ladies compartment is usually the first bay, right next to the entrance. This used to be protected by a "closed" shutter, but I think that is no longer the case. Apart from being very claustrophobic, this is usually crowded and noisy, with women and children. I consider them to be all the more risky affair than the "open" compartments.

Most trains do not have a gender specific quota, and as far as I know women only compartments are available only in Sleeper or non-A/C classes. Selecting this criteria might just reduce your chance of getting a confirmed berth.

• Avoid Sleeper class. It's always crowded, and vendors keep streaming in and out.
• AC coaches are safer and they also have an attendant (though may be be difficult to get hold of most of the times).
• Second AC has two berths per side. There are curtains on all sides for privacy, but this may or may not pose some other problems.
• Third AC is ok, with no curtains and three berths per side. This is the one I prefer.
  Avoid First AC like plague. Politicians and their goons use them (not exclusively, of course) and there have been incidents of molestation and rape.

No matter what class you book, avoid the side upper/lower berth. This exposes you to the people using the passage way. The creeps tends to feel you up/try to molest you at night.

   ======= | P | |S|
   Row 1   | A | |i|
           | S | |d|
   Row 2   | S | |e|
   ======= | A | 
           | G |
           | E |

Second AC (2AC class), I won't recommend above and below this class.

I am avoiding 1AC (first AC) as generally politicians and their caretakers use this class, and many of these peoples are not worth travelling with safely :-).