How to get to Bangkok Death Railway?

Your options are:

By train, you might be able to connect from Hua Lumphong Station (or Bang Sue Station) to Tailing Chan Station, which is on the Nam Tok and Southern Lines. ...
By taxi from most of Bangkok will cost 150 to 200 THB. ...
River ferries plying the Chao Phraya stop at Thonburi Railway Station Pier.

What time is the Death Railway train?

Two trains operate daily: Local Train No. 257 departs at 7:45 a.m., and No. 259 departs at 1:55 p.m. If you plan on returning on the same day, it is advisable to catch the earlier train. Regardless of the distance travelled, foreigners are required to pay a fixed fare of 100 Baht for this line.