Railway Investigation Report R11T0016

On 26 January 2011, northbound CP freight train 221-25 (train 221) was en route from Toronto to Sudbury, Ontario. It comprised 2 head-end locomotives and 31 empty freight cars, weighed 1367 tons and was 2013 feet in length. The crew was familiar with the territory, met fitness and rest standards and were qualified for their positions. At about 0300, ¹ train 221 pulled into the siding at Buckskin, Ontario and stopped (Mile 103.0 of the MacTier Subdivision) to clear the main track for the passage of southbound CP freight train 220-24 (train 220). 
On 25 January 2011, at approximately 1715, CP freight train 220 departed Sudbury, destined for Toronto. Train 220 consisted of 3 locomotives, 43 loaded cars and 19 empty cars. It weighed 6482 tons and was 4382 feet in length. At Mile 112.7 of the Parry Sound Subdivision, train 220 transferred to Mile 247.5 of the CN Bala Subdivision. While proceeding on the Bala Subdivision, train 220 passed over 8 CN hot bearing detectors (HBD).²
There were no alarm level thresholds recorded for any of the cars on train 220. HBD readings for the train are summarized below:

Summary of CP Railway Train 220 HBD readings on CN Bala Subdivision

Location	Mile	East Rail (mm)	Train East Rail Avg. (mm)	West Rail (mm)	Train West Rail Avg. (mm)	Low Level Alert	Alarm
Waterfall	245.4	3.8	2.8	3.8	2.7	no	no
Burwash	230.8	5.4	3.7	7.4	3.6	no	no
Bayswater	218.2	5.5	3.8	6.2	3.6	no	no
Key Junction	202.7	4.9	3.6	8.7	3.9	yes	no
Drocourt	187.0	6.0	4.3	7.5	4.1	no	no
Ardbeg	175.2	6.1	4.1	8.7	3.9	yes	no
Waubamik	163.2	5.3	3.5	8.7	3.4	yes	no
North Parry	152.5	5.5	4.1	8.9	4.1	yes	no

For 4 of the last 5 CN HBDs that train 220 encountered on the Bala Subdivision, the L4 roller bearing on car SKPX 625514 recorded readings that initiated a low level alert. CN low level alerts are below HBD alarm threshold levels, and do not require any action. Although the HBD system records the low level alert, it does not always generate an automatic alarm message to the CN RTC Mechanical Technician ( RTCMech) in Edmonton, Alberta.
At 0156, the train crossed back on to CP trackage (Mile 20.1 of the CP Parry Sound Subdivision) at Mile 146.2 of the Bala Subdivision. The CN low level alerts were not communicated, nor required to be communicated, to either the train crew or CP. At about 0230, the train stopped for a crew change in MacTier, Ontario (Mile 0.0 of the Parry Sound Subdivision and Mile 126.9 of the MacTier Subdivision). The inbound crew conducted a pull-by inspection on train 220 with no exceptions noted. The outbound crew was familiar with the territory, met fitness and rest standards and were qualified for their positions. At about 0240, train 220 departed southward on the MacTier Subdivision. The next HBD that train 220 was scheduled to encounter was located at Mile 98.1 of the CP MacTier Subdivision.
At approximately 0315, train 220 approached the Buckskin siding at Mile 103.7 of the MacTier Subdivision. Train 221 was in the siding, clear of the main track when its crew observed that a car on train 220 was derailed. Train 221’s crew immediately made an emergency radio broadcast and tried to exit the locomotive cab. However, both cab doors were in the path of the derailing train which prevented its crew from exiting. Train 221's crew took cover in the cab where they remained until train 220 came to a stop. Train 220's crew initiated an emergency brake application at 0315:32, while in throttle 2, travelling at a speed of >44 mph. The train came to a stop at 0316:36.
There were no injuries, and no loss of product. At the time of the derailment, there was light snow falling, a temperature of -40 C and light northerly winds.

Emergency Response

CP's Field Manager of DG (FMDG) was called at about 0400 and responded to the occurrence from Montreal, Quebec. The FMDG then contacted and deployed CP's trained and qualified Emergency Response (ER) contractors and provided direction while enroute to the occurrence site.
Derailed car PROX 33743 (45^th car on train 220), a loaded dangerous goods (DG) tank car containing non-odorized liquefied petroleum gas (UN 1075), sustained damage to its outer jacket. Frosting on the jacket was observed, which indicated that it may be leaking. The first contractor arrived on-scene at about 0830 and conducted a preliminary visual inspection of PROX 33743 which revealed that there was no leak. Upon the arrival of the second contractor, a second instrumented assessment of the car was conducted. This assessment also confirmed that there was no leak. This information was relayed to the enroute FMDG. As a precaution, the FMDG requested that the hot zone be maintained until his arrival. An 800 meter exclusion zone was then set up and 15 families were evacuated.
The site was declared safe about 9 hours after the derailment and residents were allowed to return home.

Site Information

A total of 21 cars on train 220 (27^th to 47^th cars) had derailed. The lead truck of the lead locomotive on train 221 was also derailed. The 27^th to 29^th cars had remained coupled to the head-end of train 220 and had side swiped the locomotives and first 9 cars of train 221, which was stationary in the siding. The 30^th to 47^th cars on train 220 came to rest in various positions in the vicinity of the Buckskin North siding switch (Mile 103.75). Inspection revealed that the L4 roller bearing in the trailing truck of train 220's 27^th car (freight car SKPX 625514), a covered hopper car with a 286 000 gross rail load (GRL) capacity loaded with grain, had failed. Subsequently, the L4 axle journal had burnt off (BOJ) and separated from the axle (see Photo 1).

Photo 1. SKPX 625514 L4 BOJ (Source: CP) ↑

Impact marks were observed on the track ties extending northward from the derailment area to a snowmobile crossing located at Mile 105.1. The severed axle journal stub was located at Mile 110.45. Between Mile 105.1 and Mile 110.45, various roller bearing components were strewn about the railway right of way.
About 400 feet of track, including the Buckskin Siding north turnout and signal structures, were destroyed. Approximately 1900 feet of track in the area of the accident and 1.4 miles of the main track approaching the siding was damaged (see Figure 2).

Figure 2. Derailment site diagram ↑

The N^o. 3 and N^o. 4 wheel sets from SKPX 625514 were sent to CP's Test Department for a joint teardown inspection with Transporation Safety Board (TSB) personnel.

Subdivision and Track Information

The CP Parry Sound Subdivision consists of a single main track that extends southward from Romford, Ontario (Mile 121.7) to MacTier (Mile 0.0). The southernmost CP HBD on the Parry Sound Subdivision is located at Mile 26.0. The CP MacTier Subdivision consists of a single main track that extends southward from MacTier (Mile 126.9) to Osler, Ontario (Mile 0.0). For trains travelling southward from MacTier, the first CP HBD encountered is located at Mile 98.1. Train movements in the derailment area are governed by the Occupancy Control System as authorized by the Canadian Rail Operating Rules (CROR) and supervised by a Rail Traffic Controller (RTC) located in Montréal, Quebec. The track is Class 4 according to Transport Canada (TC) approved Railway Track Safety Rules (TSR). The maximum speed permitted is 50 mph for expedited intermodal freight trains. Rail traffic through this location consists of approximately 29 freight trains per day with an annual tonnage of about 30 million gross tons.
Throughout the derailment area, the track consists of 115 pounds. continuous welded rail. The rail was laid on 14 inch tie plates, secured to hardwood ties with 6 spikes per tie, with every second tie box–anchored. The ballast consisted of crushed rock and slag. The cribs were full and the shoulders extended from 12 to 24 inches beyond the end of the ties. Between Mile 105.1 and Mile 103.7, the track descends gradually in the southward direction.
Track inspections were performed regularly in accordance with the TSR. During the most recent  inspections, no track anomalies had been observed at this location. The Buckskin siding is 7650 feet long and runs parallel to the west side of the main track between Mile 103.75 and Mile 102.15.





Wheel sets are assembled in compliance with the Association of American Railroads (AAR) Manual of Standards and Recommended Practices (MSRP), Section G, Part II. The MSRP sets forth the minimum manufacturing standards for practices related to wheel set manufacturing and reconditioning. Wheel set assemblies consist of 2 wheels, which are bored and pressed onto an axle wheel seat, and 2 roller bearing assemblies pressed onto the axle journals. Once the wheels are mounted, the wheel mount date and shop identifier are stamped on the outboard hub of one of the wheels. Then, roller bearing assemblies are mounted on the axle journals.
During wheel set assembly, new roller bearings are only matched with new roller bearings, while reconditioned roller bearings are matched with reconditioned roller bearings made by the same manufacturer. Reconditioned roller bearings account for the majority of roller bearings in service today.
A roller bearing assembly consists of an outer cup which houses 2 tapered roller cone assemblies separated by a spacer. Each roller assembly consists of a raceway, rollers and a cage. Inboard and outboard seals, seal wear rings, a backing ring and an end cap complete the roller bearing assembly (see Figure 3). The cup, rollers and cones are case hardened with precision finishes for the closely matched mating surfaces.
The cage is essentially a spacer that retains the rollers in place within the cone assembly. In the case of the failed L4 roller bearing from SKPX 625514, the cage was punched (cold formed) from a sheet of low carbon malleable steel.

Figure 3. Roller bearing components (Source: Timken AP Bearing Parts) ↑
The entire assembly is pressed on an axle journal, seated against the axle journal fillet radius and it is retained by an end cap, secured to the end of the axle, with 3 cap screws fixed in place by a locking plate.
AAR MSRP, Section G, Part II, Rule 1.8.6.2 states (in part) that roller bearing locking plates shall be stamped or legibly etched with the following information:

• N = if new, and (mm/yy) indicating month and year of bearing manufacture (same as stamped on the outside of the cup) as well as company and shop identification marks of mounting shop.
• R = if reconditioned, and (mm/yy) indicating month and year of bearing reconditioning, as well as company and shop identification marks of reconditioning shop.

For wheel sets that have wheels and bearings mounted at the same time, in new or remount assemblies, the locking plate information closely matches the wheel press-on information. For wheel sets that have been reconditioned through a wheel shop and have had wheel treads re-profiled and/or roller bearings replaced, the locking plate information will not match the wheel mount information.
In some cases, AAR maintenance advisories and recalls require railways to inspect the roller bearing locking plates in order to identify potentially defective wheel set components and remove them from service.

Roller Bearing Reconditioning Standards

Approximately one million new or reconditioned bearings are mounted each year by North American railways. Roller bearings are assembled in compliance with the AAR MSRP, Section H-II, Roller Bearing Manual, which sets forth the minimum standards for roller bearing manufacturing and reconditioning. Roller bearing reconditioning comprises the disassembly, cleaning, inspection, repair (if necessary), and reassembly of the roller bearing.
Roller bearings are designed to last the life of the wheel set without additional lubrication or maintenance. The AAR does not require roller bearings to be removed for any age or mileage criteria. However, when a wheel set is removed from service for any reason, the roller bearings must be removed, inspected and reconditioned in accordance with the AAR MSRP, Section H-II Manual.
For new roller bearings applied to the same wheel set, manufacturing dates generally match within a month or so of each other. For reconditioned roller bearings applied to the same wheel set, reconditioning dates are generally close.