Page created by Tommy McGowan

Note:  this page doesn't go too much into the technical details on how the mechanisms operate.  The main purpose is to show the change in design of the gate mechanisms over the years and to help identify the age of signals.

The AL-70 is the earliest version of the WABCO gate mechanism. They have unique counterweights in a triangle shape, and there's an even older version similar to the Safetran Model 85 mechanisms, but I don't have any photos of them. I have seen a WCH gate mechanism with a WABCO triangle counterweight in Berwyn, IL, but otherwise, this was uniquely on WABCO/US&S mechanisms.

The Model 75 received a more traditional counterweight, and this design would continue to be used on Model 95 gate mechanisms. I'm not sure when the Model 75 was discontinued.

This was the first style used on US&S Model 95 mechanisms. These were primarily seen from the 90s into the mid to late 2000s. The major identifier of the earlier Model 95s is the narrow font used on the "Model 95" on the right side of the mechanism, and it protrudes out quite a bit. The US&S logo on the left is also smaller in this version.

Style 2 was very similar to Style 1, the only difference being the lettering on the side. The "Model 95" is now fatter and doesn't protrude out as much, but the US&S logo was the same size. This started appearing in the mid to late 2000s.

Style 3 started showing up in the 2010s, and the US&S logo is now much bigger and doesn't protrode as much, and the Model 95 lettering is now narrower similar to Style 1, but now much smaller. The 2 ribs on the bottom of the cover have also been removed. These are not very common to find, as not many railroads use US&S mechanisms anymore.