By Daniel Garcia and James Bow.

These engines where originally built in 1967 for the Rock Island, as GP40-M2's. These engines, with the exception of being older and not having a safety cab, were almost exactly the same as the GP40-2L, right down to operating without an HEP generator. They were rebuilt in 1982 at GMDD in London and shipped to GO Transit. When GO Transit bought these engines, they had to buy more APCU's to compensate for the lost HEP. The GP40us were designated class GCE-430f and arrived as numbers 720-726. They kept those numbers for their whole career.

GO Transit was able to purchase these locomotives at a bargain rate, thanks to the recession that had gripped North America and its railroads in the early 1980s. The GP40u's were used for 12 years, and were traded back to GMDD as part of the purchase of the last order of F59PH's in 1994.