When ILW entered the locomotive market, they had Dofasco & Canadian Steel Foundries doing the castings for their diesel trucks (and after the Portland Shops developed a line of radial trucks, for the locomotives they produced for the Parsons Vale, Amtrak, and various commuter districts.)
Unfortunately, Canadian Steel Foundries went belly up in 2004, and then Dofasco shuttered their castings division in 2014, leaving no AAR-certified Canadian foundries to produce the top frames for ILW locomotives.
For a few years ILW reluctantly ordered truck frames from Bradken-Atkinson (ILW very much preferred to use Canadian sources for their locomotive parts) but the cost of the big articulated trucks that ILW built for the Portland Shops was more than they wanted to spend. So they started shopping for alternatives.
Before the Portland Shops developed their radial trucks, they’d been fabricating welded plate frame trucks for their motors. These trucks had been tested to within an inch of their lives, both on Parsons Vale tracks & at the Transportation Technology Center in Colorado, so the fabrication was known to be good. And even though the radial trucks used a cast topframe and didn’t need a fabrication department in Portland anymore, most of the workers who’d built those frame were still working in the Portland Shops (some of them had retired in the interim, some had gone elsewhere in the industry) and were happy to participate in a test project to build welded plate radial truck frames.
ILW hired most of the remaining Portland Shops fabrication workers, and set up a subsidiary to only build trucks (thus “ILW Truck”) for ILW, the Portland Shops, and whoever else might want to use the Portland radial truck design on their locomotives.
Initially, ILW leased space in the Saint-Jean-sur-Richelieu shops complex, but property became available close to the old Alco site in Schenectady, so a new facility was built there instead.
As of 2024, ILW Truck makes fabricated plate frames for all of the Portland radial truck designs, mainly for ILW & the Portland Shops, but there is a small but steady stream of orders from other locomotive builders.