This is a railroad locomotive brake valve handle. This would be carried by the locomotive engineer . The square hole would fit over the brake valve shaft and the spring loaded blade would be used as a detent to help identify and keep the brake handle in the proper position. The spring-loaded detent would fall into notches that were around the shaft. Although I don't know the exact vintage of this brake valve handle, I have a similar one from a 1955 Pennsilvania railcar. The manufacturer would most likely be Wabco, that is Westinghouse air brake company. There are many railcar museums that may be interested in this brake valve handle . There are several on eBay and many on google images.

This is a railroad locomotive brake valve handle. This would be carried by the locomotive engineer . The square hole would fit over the brake valve shaft and the spring loaded blade would be used as a detent to help identify and keep the brake handle in the proper position. The spring-loaded detent would fall into notches that were around the shaft. Although I don't know the exact vintage of this brake valve handle, I have a similar one from a 1955 Pennsilvania railcar. The manufacturer would most likely be Wabco, that is Westinghouse air brake company. There are many railcar museums that may be interested in this brake valve handle . There are several on eBay and many on google images.

References:

Check out eBay item #282019659732 and # 162053990591 in brass