When the OSW purchased the Canadian section of Conrail’s CASO (the CPR & CN were primarily interested in the Michigan Central Tunnel, which the OSW was happy to not include in their purchase,) the Michigan Central yards & industrial trackage at the Windsor end of the tunnel were split between those three railways by the simple expedient of setting up a jointly owned terminal railway (the Windsor Terminal Railway) as a neutral operator.
Initially, the line was dieselised, but the OSW electrified the whole thing in 1989 to reduce pollution from yard operations. This was first operated by a pair of ex-Conrail E44 motors, joined later by (converted to multi-system & equipped with third rail shoes just in case) prototype class J conversion #619, then, in the 2000s, the E44s were replaced by three class M motors.
The United Railways Trust merger brought one extension (the CPR transferred ownership of the Michigan Central tunnel to the Windsor Terminal) & two new owners for the railway; Conrail Shared Assets and the Essex Terminal Railway got minority shares in the property (making the ownership OSW 26%, CPR 25%, CNR 33%, and Conrail & the Essex Terminal each with 8%.) It still operates as neutral operator, even though the OSW & CPR now route all of their through trains through the CTRC’s South China Tunnel.