Charles Burrell & Sons of Thetford, Norfolk were builders of steam traction engines, agricultural machinery, steam trucks and steam tram engines. The firm operated from the St Nicholas Works in Thetford and built over 4000 steam engines between 1848 and 1928. Burrell were famous for their magnificent showman's engines, but I haven't been able to find out what these small-scale versions were used for - was it agricultural work?