CN's SW1200RM program utilized an SW1200RS as the base for the new locomotive, resulting in the GS-413a and GS-413b classes. To create the locomotive, the SW1200RS's frame and cab were combined with the long hood from a retired GP9. The inoperative dynamic-brake blister was fitted with air-intake filters, and the 12-cylinder 567C engine was upgraded with 645C components to increase the horsepower to 1,300. The cabs were also improved with a modified end-window arrangement, better insulation and heating. Additionally, the rear door was modified to hinge outward for increased collision protection.
The first SW1200RM was produced in April 1986 at CN's Pointe St. Charles shops as locomotive numbers 7300 and 7301 respectively. They were later renumbered to 7100 and 7101, with the remaining locomotives in the first phase of production designated as 7102-7107.
After remanufacturing eight GS-413a Sweeps between April 1986 and May 1987, CN determined that the additional 100 horsepower gained by incorporating the GP9 hood and cooling fans onto the SW1200RS did not warrant the expense. As a result, CN ceased production of the 'Sweep' after producing only eight examples.
This variant models CN number series (7101) GS413a
Recommended Chassis - Athearn SW7