Saturday, 30 November 2019

CN Stuart Street Diesel Shop – Sanding Operations

Tucked in behind the pint-sized diesel shop at the Stuart Street Yard was a structure common to most locomotive servicing facilities; a tall, somewhat spindly appearing sand tower.
Traction sand has been a component of railroading ever since the creation of the steel wheel on steel rail combination. Given the inherent low level of contact friction and minute contact area, augmentation of steel on steel traction is essential. Grip for initial movement, smooth acceleration and controlled braking are all dependent to some degree upon proper sanding. Sanding also helps to maintain traction and motion on greasy rail conditions caused by moisture, oil or fallen leaves. Traction sand must be fine, uniform grain, free from contaminants, and most importantly, dry. First generation F units and switchers were typically equipped with four sand fill/hoppers located more or less above each truck side frame. Dick Dilworth’s legendary ‘Geeps’ had a single sand fill located in the prow of each high nose, with internal piping down to each side. Most modern locomotives are similarly configured, although so called ‘safety cab’ locomotives have two fill hatches either side of their wide nose. Delivery of sand to the rail head is accomplished via flexible rubber hoses and nozzles secured to the ends of each truck side frame.
CN SW1200RM 7106 was originally constructed by GMD London as SW1200RS 1257 in January of 1957. Remanufactured in 1987 at Pointe St. Charles, No. 7106 would be included in the sale of all eight SW1200RM’s to Canac in February of 2000. The unorthodox looking unit would subsequently be acquired by Savage Rail Services as their SVGX 7106.
CN SW1200RS’s 1311 (GMD 1958) and 1338 (GMD 1959) along with an unidentified sister in the background gather around the shop.  No. 1311 would depart the roster in 1994 to Ohio Central while No. 1338 would hang on until 1998 prior to being sold to Canac. Note that the sand tower distribution booms span tracks on either side. Note also the flexible hoses that permit sanding on both sides of the locomotive – a necessity as most locomotives are equipped with sand hoppers positioned directly above the truck side frame on either side. Most sand towers are painted silver so as to reflect rather than attract heat which could lead to condensation within the hopper.
Details at the top of the hopper included piping and venting fittings along with a ladder and safety railings for maintenance. A flood light, out of sight on the opposite side, facilitated around the clock operations. Note the power line on the right hand side. Filling of the hopper is accomplished using the small diameter vertical pipe leading from a sealed storage bin to the top of the structure and compressed air. Topping up of locomotive sand boxes is simply a matter of gravity. Absence of internal moisture is vital to the entire sanding operation.
Blomberg Type ‘M’ rear truck on GP40-2L(W) No. 9468 (GMD 7/1974)

The compact two-stall diesel shop structure, constructed in February of 1964, remained relatively unchanged over the years. Updates included additional lighting positioned along the roof top at the rear, and, perhaps due to misadventure, new roll-up doors on more than one occasion. Note the lightning rod on the left hand roof top corner of the building; no doubt a requirement related to the fuel storage tanks at the front and side of the building and out of sight to the left hand side of the structure. Sadly, most of the noticeable change towards the end was due to lack of maintenance and neglect.
CN SW1200 7033 was constructed by GMD London in 1957. In 1985, in order to clear the number series, the entire remaining group of switchers (7020 – 7034) were renumbered to 7720 – 7734. All would be off the roster by 1990. Note the small, horizontal diesel fuel supply tank on the right. Tucked in behind No. 7033 is MLW S-4 No. 8166.

No comments:

Post a comment