|Y||Yorkshire Patent Steam Wagon Co||Rail|
This company produced quite distinctive steam lorries with their patented double ended boiler in their works on Pepper Road Hunslet. They dabbled with internal combustion engines and produced specialist bodies for commercial vehicles such as the gully emptiers that featured on some of their own steam wagons. The last steam wagon left the works in 1931 but the Yorkshire Patent Steam Wagon Co name was retained for a further 40 years
Note - there might be a few builders in this list that are not in Leeds as they built Leeds designed locos as sub contractors.