NAS has Westinghouse 50DHP parts.
The following is available as a whole or seperate.
50DHP75 , 50DHP150 , 50DHP250 , 50DHP350
Whole assembly PN: 6426C73G01
Stationary Arching Contact Assembly PN: 501B812G01
Stationary Main Contacts from the above assembly
PN: 506A098G02 right hand side
PN: 506A098G01 left hand side
Available at www.naswgr-store.com