MTA Work Cars

Long time fan of subways, Philadelphia born and raised. Been looking through NYCsubway.com, which I look at once a week or so. A question on some of the subway work cars, as to their purpose.

R123 Continuous Welded Rail Car. What is the Weld Car?

R161 and R71 Rider Car. Used to carry maintenance crews?

R65 Pump cars

R71 reach cars. Working on the ceiling?

R74 Signal Supply cars

Rail Adhesion cars

Tank cars.

OF116 Obsrvation Car. Early track geometry car?

The others shown on the website are pretty much explanatory.

OF-116 "Theater type" track inspection car for " Official use",showing off the system to the political types like the Mayor or Governor.
Rail Adhesion Cars, Sprays a sandite solution on the rail(surface/elevated lines) to combat Wheel sliding/Wheel spinning during fall and
winter seasons. Works with Alcohol spray cars that deice the 3rd rail.
Reach Cars, used to extend the "reach" of Pump cars into areas needing to be pumped out of water,carry power to the pump car and the discharge hose
to the nearest working sewer drain.
Signal Supply cars, used to carry parts of the signal system to the work site.
Rider cars,Carry work crews to the work site.
Welded Rail Cars, Carry limited amount of CWR strings to work site,rail is offloaded thru hole in floor of 1 car of the set.
Tank cars carry the water/solutions used by the wash train to the work site.
Most of the NYCTA work cars are "Homebuilt/Kitbashed" at shops across the system,very few are purpose built by outside vendors.

Got it, thanks