Thank you to Jim Aldridge for the previous list of designations for PRR switch locks keys.
I have obtained another style of key which I think belonged to the M of E Dept,being that the tab comes off the barrel on the left side at an approx 45 degree angle towards the center of the barrel. The initials and the numbers on this key are PT414 S.
Can anyone provide any information on this style of key as to the number and initials with reference to a region & division.
Thank in advance to all who respond.