Since their invention in 1814 by Briton George Stephenson, trains have helped transform the world. Now you can witness their evolution, from the first engines to the latest bullet trains. More than 560 stamp exhibits featuring trains are on display at Postal Gallery in the General Post Office in Central until November 24. The stamps tell many fascinating stories. In one of their earliest forms, trains were simply carts which were pulled by horses along sets of rails - rudimentary but effective, and that's why they were still being used in the 1930s. A Vietnamese stamp suggests that the technology involved in the locomotive engine was known to the country years before its 'official' invention. 'It was really a steam engine,' said chairman of the Chinese Philatelic Association, Cheung Kam-che. 'You can see the huge boiler on some wheels.' China's first stamps with a train design were issued in 1913 under the Nationalist government. 'Railways had been operating in China for some time, but all were managed by foreigners,' said Mr Cheung. 'Dr Sun Yat-sen believed that China needed its own railway. When the stamp was brought to him for approval, he asked for trains to be added.' You will be disappointed if you expect to see very expensive stamps. 'None of them are very costly,' said Mr Cheung. 'But you can learn a lot from them.'