Before diesel engine, stream engine must had been used in Hong Kong's railway. I would like to know when did it happen and like to see some foto of these stream engine.
Yes, they did. The Kowloon-Canton Railway British Section (MTR East Rail Line nowadays) used to be operated by steam engines from the opening in 1910 until 1962, with the first diesel loco entered service in 1955. The first diesel loco (fleet number 51) & one of steam engine that served Sha Tau Kok Branch in 1920s were becoming exhibits in Hong Kong Railway Museum (the old Tai Po Market Station). You may try to search the photos related to KCR BS before 1960s on the internet, as the museum was closed due to the pandemic.