Due the the heavy amount of daily road traffic in Bangkok one of the fastest and most time efficient ways to get around parts of the city is via the BTS (Bangkok Mass Transit System) also known as the Skytrain.   BTS Skytrain operates from 06.00 - 24.00 hours everyday with two main lines -- Sukhumvit and Silom lines. Passengers exchange between lines at Siam a one day pass can be purchased for 100bt and is valid for as many journeys as you want until the end of that day.