Friday 24 September 2021

CN Stuart Street Yard – PSC SW1200RM

While a crown corporation, Canadian National benefited from rather unique fiscal circumstance. Unaccountable to share holders, the railway could deploy monies to discretionary endeavours, such as Research and Development, without undue monetary scrutiny. Not that this was unfruitful. Via R&D CN developed the industry standard locomotive ‘Safety Cab’ and played a significant role in the creation of traction control (see the CNRHA book CNR Diesel Locomotives – Vol. II). Another optional expenditure: locomotive rebuilding. While most Class One roads engaged in motive power remanufacture, CN’s were among the most extensive, in both volume and scope. Best known is the GP9RM rebuild program. The elaborate remanufacturing process more than doubled the life of a couple hundred of Dick Dilworth’s masterpieces. Not nearly as numerous, but perhaps more drastic appearance wise was the SW1200RM, or ‘SWEEP’ (as the unit was affectionately known). Seeking to create a more capable/reliable switcher, PSC upgraded the prime mover (567C to 645C/1300 HP), improved cooling by grafting a GP9 hood (switcher type cooling via belt driven fans had long been a maintenance headache), and enhanced cab creature comforts (insulation/heating/hot plates/refrigerator). For more details see pages 170 – 171 of CNR Diesel Locomotives Vol. II. Only eight SWEEP’s were completed; CN ultimately decided to remanufacture a small group of SW1200RS’s in kind, and deploy 7000/7200 series GP9RM’s into yard service (often with accompanying slugs).

CN 7103 was constructed as SW1200RS CN 1238 in July of 1956. Together with improved insulation and heating, cab amenities were enhanced with hot plates and refrigerators. Compare the rear of cab door and window arrangement between 7103 and 7315. To improve collision protection PSC applied a thicker outward opening door and reconfigured the window geometry to multiple same sized panes.

Aside from SW1200RS CN 1374, something of a Pointe St. Charles remanufacturing showcase. From left to right: GP9RM CN 4124, SW1200RM CN 7105, GP9RM 7263 and slug CN 256. CN 4124 was constructed as GP9 4530 12/1956 and departed the roster in 2009. CN 7105 departed GMD London as SW1200RS 1253 in late 1956. CN 7263 (GMD 9/1957) was originally GP9 4117 and served her one and only owner until being retired in 2019. Slug 256 (GMD 12/1956) was constructed as GP9 CN 4529 and retired by CN in 2007. CN 1374 was built in April of 1960. Renumbered CS04, the end cab unit was retired in 2003 and scrapped in 2018.
No. 7106 was originally constructed as CN 1257 at the beginning of 1957. Similar to the balance of the ‘SWEEP’s’, the modified unit would join the Savage contract switching fleet as SVGX 7106.

In ‘BEFORE & AFTER’ staging, CN SW1200RM’s 7303 and 7104 portray the Pte. St. Charles’ effort to create a super switcher or ‘SWEEP’; SWitcher + gEEP. CN 7104 was constructed as SW1200RS CN 1248 11/1956, while CN 7303 was delivered from GMD 4/1960 as CN 1370. All eight SWEEP’s were sold to CANAC in February of 2000. CN 7303 departed the roster in 2010 to become GMTX 507.

CN 7102 was delivered from GMD London in May of 1956 as SW1200RS CN 1230. Post CANAC ownership the compact unit would be acquired by Savage Inc. ( to join their contract switching fleet. Increased cooling capacity provided by the GP9 hood style radiator and fans provided for a HP increase to 1,300. Similar to the GP9RM, the inoperative dynamic brake geometry was redeployed as air intake and fitted with filters.