Source: UNESCO World Heritage
Postcard 1A - Darjeeling Himalayan Railway
Darjeeling Himalayan Railway - DHR, was bulit between 1880-86. Thanks to Siddhart of India.
Postcard 1B - Darjeeling Mountain RailwayDarjeeling Mountain Railway mailed supposedly by sea on Nov 27, 2019 but arrived in Penang island on December 16, 2019 - perhaps by airmail. Thanks to Biju of Kerala, India.
Postcard 2 - Nilgiri Mountain RailwayNilgiri Mountain Railway of India at Ooty. Thanks to Claus.
Postcard 3 - Kalka Shimla RailwayKalka Shimla Railway. Thanks to Bhat of India.