Robert Sinclair (1 July 1817 – 20 October 1898) was born in London but came from a Caithness family.
He became Chief Mechanical Engineer of several British railways and also worked in France.
[1] He was apprenticed to a shipbuilder and later worked for Robert Stephenson, the Grand Junction Railway and the Paris and Rouen Railway.
[2] Sinclair resigned from the GER 1865, and became a consulting engineer.
The Luxembourg 2-4-2 design was later adapted into a 2-4-2T for commuter services on the GER.