The Darjeeling Himalayan Railway, which originates at Siliguri, is called the Toy Train.
But the best way to travel up at least part of the way, if you're too impatient to take 6 hours for the whole 80 km (50 miles) is by the Darjeeling Himalayan Railway, more popularly and humorously known as the Toy Train, which starts out at Siliguri, not far from Bagdogra.