Not only has it never been used, the track isn't even connected to anything anymore. It used to be a spur into the Regional Market that served a couple of other customers ages ago, but was disconnected when the Regional Transportation Center was built. Somewhere I have a shot of a CNW boxcar derailed in there around the curve where the tracks are now pulled up.
For Ontrack, the plan was to extend the track along the main line (Former CR #7 IT I believe, itself extended from the 292.7 hand throw switch down to the mall) from the mall platform across Park Street on the east side of the RTC platform and then tie into this spur. The biggest obstacle to this is the former NYC bridge across Park Street is only two tracks wide for whatever reason. So another bridge next to the existing one would have to be added. But that area is all filled in swamp and when they started trying to drive pilings and such for the bridge - which was purchased and sat in the RTC lot for several years (until the county sold it for scrap at a huge loss, no less) Conrail made them stop out of fear it would cause damage to the existing structure, apparently it was causing it to shift, as the ground isn't that stable there (fun to think about when driving over all this on I-81). IIRC two attempts were made to build a support for it and both times they had to stop. Now that CSX has redone the abutments for their bridge I don't know if that would make a difference or not.
So no bridge, no connection to the new station, no connection to the ball park platform, made the whole thing more or less redundant. Eventually this became obvious to where they ended the shuttles, although that could have been managed better if they really wanted ridership to grow, too.
But remember Ontrack was just more or less a scam in the first place. It was Walter's way to get the county to force Conrail out of the former DL&W from Jamesville to where it ties into the main line at CP-293 and via the Salt Land Spur connector, which Conrail didn't want to sell. He needed this portion of the line so it could be rehabbed for freight traffic, so he could remove the Sea-Land/CSX stack trains from the former D&H portion of the route from Buffalo to Binghamton. Which in itself was a retaliation for the bankruptcy court awarding the D&H to CP rather than to his investor group. By then those stacks came into Buffalo from the west on Conrail anyways, so extending them to Syracuse was no big deal (I believe prior to 1988 they came up the now-B&P into Buffalo). I actually went out to catch the first train on this routing - at night, so I set up some time exposures with the camera that came out pretty nice.
My guess is one day you may see that entire bridge replaced so they can widen Park Street to four lanes with shoulders, due to the traffic levels there, and perhaps they'll build a three or four track structure then, but I wouldn't hold my breath waiting to see it.
Actually, I take it back. Two ex-Metro North/NYC RDCs did use this track once, maybe about 1990. Conrail was delivering three to I believe somewhere in Indiana and derailed them, damaging one pretty badly on the end. They stuck them in this siding and donated them to the CNY NRHS who parted them out.