I found some pics online of FRR's locomotives. There are also several online sites with information about the 'upside-down' bridge, the engines, FRR, rails lines in WNY...Many many sites...
It seems that the FRR line is small but also connected to other bigger lines that occasionally use this section of the line. Genesee Valley seems to have an interest in it as their engines are sometimes seen in the Lockport rail yard.
Wikipedia has a page on FRR describing the engines -
Engine roster
The Falls Road Railroad, like all other GVT properties, is Alco-powered. The railroad uses one New York Central vintage RS32 (2035) as well as one Nickel Plate vintage RS-11 (1802). The 2035 is the primary engine; however, 1802 will be used on days when an extra train, such as a passenger excursion or snowplow, is needed.
https://en.wikipedia.org/wiki/Falls_Road_Railroad
https://www.gvtrail.com/region/western-new-york/
https://historicbridges.org/bridges/...ss/lockportrr/
I believe that last pic of mine in post #1 shows the snowplow parked at the rail yard.