Optimizing the system on CPR's BC South Line: Despite the use of premium components and a high level of maintenance, wear and degradation on the line persisted - Canadian Pacific Railway - Statistical Data Included

Railway Track and Structures, July, 2001 by Mike Roney, Dave Meyler, Eric Magel, Peter Sroba

The CPR-TF profile is applied to the higher-speed and crushed-head sections of tangent track, while the CPR-TG profile, which is inherently more vulnerable to hunting, is used in lower-speed regions. These tangent profiles are applied in approximately equal lengths of track over the route.

Individually, these profiles will reduce fatigue and wear at any given section of track. Together, they should further reduce the number of hollow wheels. By limiting wheel hollowing, the two tangent rail profiles will extend the life of the wheel and rail (especially the low rail), improve stability and reduce fuel consumption.

In addition to implementing improved rail profiles, CPR also set about to increase grinding production rates and to reduce the cost of grinding per finished mile. Cleaner, harder rail steels that are resistant to fatigue and plastic flow, and the latest generation rail grinders that can grind a wider variety of patterns faster and more accurately have all contributed to extending the grinding intervals on CPR.

After a comprehensive assessment of the risks, CPR eliminated an entire cycle from its grinding program, extending grinding intervals on sharp curves from 18 mgt to 25 mgt. Detailed field review has found few adverse rail problems due to the extended grinding interval. (2)

To improve vehicle performance, and ultimately wheel and rail life as a consequence of better vehicle curving, CPR adopted the use of steerable, frame-braced trucks on all new cars in its captive coal-car fleet. In early tests, wheel flange wear on steerable trucks was 75 percent less than on standard trucks.

Further study of 240 cars equipped with steering trucks found that CPR's wheel shelling rate was reduced by about 65 percent. Average wheel life has increased 36 percent on these cars even as axle loads have increased from 33 tons to 36 tons over the same period. Add to that fuel savings of about 5.8 percent during controlled tests.

As part of a strategy to address wheel shelling, CPR has experimented with an improved wheel profile. Currently a user of the industry standard AAR1B wheel profile, CPR was encouraged by the successful implementation of a custom profile at the Quebec Cartier Railway Company. (3) Field testing on the CRC of a NRC-designed "worn-wheel" profile found a 60-percent improvement in wheel-life when tested head-to-head against the AAR1B.

The profile, which incorporates 1.6 mm (0.06 inches) more steel in the flange root, was designed to minimize creepage and the contact stresses that contribute to fatigue-related shelling.

Following the same principles, the NRC designed for CPR and CN a profile called the NRC-ASW. CPR reprofiled 800 wheels on cars in its captive coal and grain fleet. After three years of field testing, the NRC-ASW profile has demonstrated a 20-percent extension in wheel life. (4)

A thin-flange version of that profile, called the ASW-MK2, has been further improved to mate better with special trackwork and is expected to demonstrate even better performance.