Locomotive Injectors

[Anonymous]

2 Questions. On an injector i belive there are 2 controls for steam and water. Which one, steam or water, does the distinctive brass handle that you pull back control? And what prevents the water from shooting into the injector from the boiler when the injector is not in use or when starting up?

[Anonymous]

On a Sellers Lifting Injector the brass handle controls both; in first position it turns on the water and all the way back turns on the steam.

On a non-lifting injector, sometimes the starting (steam) valve is in the cab, but usually both steam and water valve handles come up through the bottom of the cab. Modern non-lifting injectors such as the Nathan 4000 have a single handle on a quadrant with the operating rod going through the floor of the cab.

Water is admitted to the boiler through a check valve which prevents steam from blowing back into the injector.

Locomotives were required to have two means for getting water into the boiler. Modern locomotives used an injector and a feedwater heater which used a mechanical pump. Both put the water in through check valves. The injector was usually on the engineer's side and the feedwater heater/pump on the fireman's side. Both sides had boiler checks, but some railroads (N&W notably) used a double check on the top of the boiler.

Old Timer