The Staten Island Railway of New Jersey is the Rahway Valley’s subsidiary that operates the (previously abandoned) section of the SIRT from the Arthur Kill Bridge to a connection with the Raritan Valley Line at Cranford, NJ.
There is currently very few customers on this line, so the Rahway Valley does not need additional motive power to operate it (there is some intermodal traffic to and from Arlington Yard, but it is all runthrough from Rahway Valley parent Eastern Pennsylvania & New Jersey Railroad.)