Can't speak for Eurail (some kind of travel pass?). However, passenger services between France and the UK are operated by Eurostar through the Chunnel. These run to London St. Pancras International from Paris, France, and Brussels, Belgium.

You can look for yourself (but remember to check the spelling of the airports city name) on this site: http://www.bahn.de/p_en/view/index.shtml
I see there are direct trains every hour, as well as trains with which you need to change. As the direct trains leave only 2 minutes later, and is only 5 minutes slower on a two hour journey, I would go for the direct trains.
There is also the odd in-between train, not every hour but if it is there when you are ready to travel you might want to go for it.

Sastri Nagar Metro station is near by Sarai Rohilla railway station, its about 1 km distance between Sastri Nagar Metro station & Sarai Rohilla railway station. Go to Sastri Nagar Metro station take metro and chenge it further at Rajiv chowck and another metro for Vaishali.

Source(s):