Engine No. 76, named "Hailsham (Terrier)

This image shows a London, Brighton and South Coast Railway (LB&SCR) A1 class steam locomotive, commonly known as a "Terrier". The specific engine is No. 76, named "Hailsham". 

The A1 class was designed by William Stroudley to haul commuter trains on the heavily congested lines in South and South-East London. 

Fifty members of the class were built between 1872 and 1880 at the Brighton railway works. 
They were nicknamed "Terriers" due to the distinctive 'bark' of their exhaust beat. 

Many of these locomotives were named after London boroughs or other areas of local importance. 

Several of the "Terrier" class locomotives have been preserved and can be seen on heritage railways today.