Rail Safety Advisory 617-02/20
Place du Centre
200 Promenade du Portage, 4th Floor
Gatineau QC K1A 1K8
04 March 2020
Letter addressed to:
Director General, Rail Safety
14th Floor, Enterprise Building
427 Laurier Avenue
Rail Safety Advisory 617-02/20
Modifying key train speed based on various train risk profiles
On 06 February 2020, a Canadian Pacific Railway (CP) petroleum crude oil unit train consisting of 2 distributed power locomotives (1 on the head end and 1 on the tail end), 104 tank cars loaded with petroleum crude oil (UN 1267, Class 3, packing group I) and 2 covered hopper cars loaded with sand (108 rolling stock in total) was proceeding eastward at about 42 mph on the CP Sutherland Subdivision. The train weighed 14 896 tons and was 6445 feet long. This was a key trainFootnote 1 operating on a key route.Footnote 2
At about 0615 Central Standard Time, the train experienced a train-initiated emergency brake application at about Mile 43.4, about 1 ½ miles west of Guernsey, Saskatchewan. Subsequent examination identified that 32 tank cars (lines 32 to 63 inclusive) had initially derailed at Mile 43.64, just west of the Bloomfield Road passive crossing located at Mile 43.63 (Figure 1).
The derailed cars were all DOT 117J100-W specification tank cars. One derailed car remained upright, was otherwise unaffected and was subsequently re-railed. Of the remaining 31 derailed cars, 19 were involved in a pool fire west of the crossing. The remaining 12 cars derailed on top of and east of the crossing. These 12 cars were not initially on fire (TSB Occurrence R20W0025).
There were no injuries reported. As a precaution, about 85 people were evacuated from the town of Guernsey. The temperature at the time of the accident was about −18 °C.
Post-accident site examination suggests that 27 of the cars lost product and released an estimated 1.6 million litres to either the ground or atmosphere. No waterways were affected. The specific number of tank car breaches sustained during the derailment has yet to be determined.
A review of the locomotive event recorder download determined that the train was handled in accordance with regulatory and company requirements. To date, no mechanical defects were observed on any of the rolling stock that could be considered causal.
A visual inspection of the head-end portion of the train that did not derail was conducted. On the north side of the train, impact marks were observed on the wheel treads of tank cars located in the 28th, 29th and 31st positions behind the head-end locomotive. The marks observed were consistent with impact that occurs when a wheel tread contacts a broken rail.
The CP Sutherland Subdivision extends westward from Wynyard, Saskatchewan (Mile 0.0), to Saskatoon, Saskatchewan (Mile 113.5). Train movements on the subdivision are governed by the occupancy control system as authorized by the Canadian Rail Operating Rules and supervised by a CP rail traffic controller located in Calgary, Alberta. The CP Sutherland Subdivision is dark territory (i.e., there is no wayside signal system and associated track circuits to govern movements and aid in the detection of broken rails).
In the area of the derailment, the single main track was classified as Class 4 track according to the Transport Canada (TC)–approved Rules Respecting Track Safety otherwise known as the Track Safety Rules (TSR). The authorized track speed for eastbound freight trains through the area of the derailment was 45 mph. At the time of the occurrence, there were no slow orders in effect.
The crude oil was transported in DOT 117J100-W tank cars, which are the newest tank cars built to transport Class 3 flammable liquids. The derailed tank cars were all manufactured by TrinityRail in 2019 and each tank car had an average capacity of about 28 500 US gallons (107 881 litres). These tank cars all had slightly thicker tank heads and shells than the Class 111, CPC-1232 and DOT 117R tank cars previously examined by the TSB. Specifically, the tank heads and shells were constructed using 9/16-inch-thick TC128 Grade B normalized steel. The DOT 117J cars were also equipped with full head shields, insulation, thermal protection, jackets and improved bottom outlet valve handle arrangements.
The type of petroleum crude oil involved in this occurrence had properties consistent with petroleum crude oil that the TSB has evaluated in previous investigations involving crude oil.Footnote 3
On 23 April 2014, following the Lac-Mégantic accident,Footnote 4 TC issued Ministerial Order (MO) 14-01 requiring railways to limit key train speed and perform risk assessments for key routes. The MO continued to be re-issued until February 2016, when the TC-approved Rules Respecting Key Trains and Key Routes came into force. The rules required railways to restrict key trains to a maximum speed of 50 mph, and further restrict key trains to a maximum speed of 40 mph within the core and secondary core of Census Metropolitan Areas (CMAs).Footnote 5
While train speed contributes to the severity of the outcome in any derailment, other factors also play a role, including train length, train weight, the position of the first car(s) derailed, the position of the cars in the train and tank car safety design.Footnote 6 In the Gladwick investigation,Footnote 7 the Board issued a safety concern and a Board recommendation related to the speed of trains transporting dangerous goods (DGs). The investigation identified that the severity of the outcome in any derailment is directly related to train speed and other factors.
One of the ways that the rail industry manages the risk of derailment is through the reduction of train speed. Historically, train speeds have been primarily based on the class and the condition of the track. Permanent and temporary slow orders can be implemented to further restrict train speed when required for operational or maintenance purposes. This has been a long-standing practice in the industry.
Over the past 10 years or so, there has been widespread implementation of the use of distributed power as train operations has evolved. This has changed the way trains are marshalled, allowing for longer, heavier trains. Similarly, train traffic has evolved as more DGs are transported in either large blocks of cars within a merchandise train or as unit trains transporting a single DG product such as petroleum crude oil.
Although managing train speed based on the condition of the track can help minimize the severity of the outcome in the event of a derailment, the risk profile of each train should also be considered when establishing a safe train operating speed. For example,
- Non-key mixed merchandise trains that transport few or no DGs and unit trains transporting non-DG commodities (i.e., grain, potash, coal) have the lowest risk profile.
- Key mixed merchandise trains transporting the minimum number of DG tank cars that are dispersed throughout the train are exposed to less risk in a derailment since the derailment could occur in an area of the train that is either not transporting DG tank cars or is only transporting a few.
- Similarly, key mixed merchandise trains that transport larger blocks of DG tank cars are exposed to more risk in the event of a derailment.
- Key unit trains of DG tank cars transporting Class 3 flammable liquids have the highest risk profile. When a derailment occurs that involves a unit train transporting Class 3 flammable liquids, the risk of release and adverse consequence is high, no matter where the derailment occurs within the train, because all cars are carrying Class 3 flammable liquids.
To some extent, TC recognized the role that train speed and train risk profile plays in the severity of the outcome of a derailment and, with the implementation of the Rules Respecting Key Trains and Key Routes, has put some measures in place to limit the speed of key trains under certain conditions. Although the restrictions contained in the rules were a step forward at the time issued, the maximum speeds were selected without being validated by any engineering analysis. The Board was concerned that the associated train speed and residual risk may be too high for some key trains. Therefore, the Board recommended that
The Department of Transport conduct a study on the factors that increase the severity of the outcomes for derailments involving dangerous goods, identify appropriate mitigating strategies including train speeds for various train risk profiles and amend the Rules Respecting Key Trains and Key Routes accordingly.
TSB Recommendation R17-01
In response to Recommendation R17-01, TC committed to conducting a literature review of existing studies on the factors affecting the severity of derailments involving DGs. TC will then assess the results of the literature review to determine if additional scientific and engineering analysis would be meaningful to further understand derailment severity factors. The results of the literature review have yet to be published, and beyond the commitment to conduct this review, there are no explicit plans for TC to revise the Rules Respecting Key Trains and Key Routes with consideration for various train risk profiles.
Immediately following this accident near Guernsey (R20W0025), pursuant to Section 32.01 of the Railway Safety Act, TC issued Ministerial Order (MO) MO-02. MO-02 further restricted the speed of key trains by requiring that railways
(1) Not operate a Key Train at a speed that exceeds 20 miles per hour within Census Metropolitan Areas or, in all other locations, at a speed that exceeds 25 miles per hour.
For the purpose of MO-02, the term Key Train means an engine with cars:
- that includes one or more loaded tank cars of dangerous goods that are included in Class 2.3, Toxic Gases and of dangerous goods (DG) that are toxic by inhalation subject to Special Provision 23 of the Transportation of Dangerous Goods Regulations; or
- that includes 20 or more loaded tank cars or loaded intermodal portable tanks containing dangerous goods, as defined in the Transportation of Dangerous Goods Act, 1992 or any combination thereof that includes 20 or more loaded tank cars and loaded intermodal portable tanks.
On 16 February 2020, pursuant to Section 32.01 of the Railway Safety Act, TC issued MO-03, which is to remain in effect until 01 April 2020. Consequently, MO-02 was repealed. MO-03 relaxed the previous MO-02 speed restrictions and introduced the following definition for a Higher Risk Key Train:
Higher Risk Key Train means a Key Train:
- where all loaded tank cars, other than buffers cars, are loaded with a single commodity that is a dangerous good, as defined in the Transportation of Dangerous Goods Act, 1992 and that is carried between one point of origin and one point of destination; or
- that includes 80 or more loaded tank cars or loaded intermodal portable tanks containing dangerous goods, as defined in the Transportation of Dangerous Goods Act, 1992, or any combination thereof that includes 80 or more loaded tank cars and loaded intermodal portable tanks.
MO-03 has the following speed restrictions in place. Railways were ordered to
- Not operate a Key Train at a speed that exceeds 40 mph in non-signaled territory;
- Not operate a Key Train at a speed that exceeds 35 mph within Census Metropolitan Areas;
- Not operate a Higher Risk Key Train at a speed that exceeds 25 mph in non-signaled territory;
- Not operate a Higher Risk Key Train at a speed that exceeds 30 mph within Census Metropolitan Areas. For greater certainty, the operation of a Higher Risk Key Train within Census Metropolitan Areas that are in non-signaled territory remain subject to the limit of 25 mph.
On 18 February 2020, 2 days after TC issued MO-03, a CN key train that conformed to MO-03 was operating on a key route. The train was proceeding eastward at about 44 mph on the CN Fort Frances Subdivision when it experienced a train-initiated emergency brake application near Emo, Ontario. Subsequent examination identified that 31 cars had derailed at Mile 108.22. The derailed cars included 27 DG tank cars, 26 loaded with petroleum crude oil (UN 1267, Class 3, packing group III) and 1 loaded with asphalt (UN 3257). A total of 5 cars released an estimated 210 000 litres of petroleum crude oil (TSB Occurrence R20W0031).
Since 2015, including R20W0025 and R20W0031, the TSB has deployed to 7 train derailments involving tank cars that were transporting petroleum crude oil. Six of these derailments resulted in a significant release of petroleum crude oil (Appendix A). A review of the accidents revealed the following:
- Five of the 7 derailments occurred in areas where train movements were governed by the centralized traffic control (CTC) system in which the train crews must follow wayside signal indications.
- Two of the 7 derailments occurred in areas where train movements were governed by the occupancy control system (OCS) of train control.
- For 6 of the 7 cases;
- Train speed ranged from 38 mph to 49 mph.
- Between 29 and 39 tank cars loaded with petroleum crude oil derailed.
- A cumulative total of 8.43 million litres of petroleum crude oil was released.
In CP’s second derailment near Guernsey (TSB Occurrence R20W0025), the train was travelling at 42 mph at the time of the accident. The derailment occurred at a speed that was permitted by the Rules Respecting Key Trains and Key Routes in force at the time. The crude oil was transported in DOT 117J100-W tank cars, which have significant design improvements when compared to legacy DOT 111A tank cars. Despite using the best tank cars available to transport petroleum crude oil, about 27 of the tank cars released an estimated 1.6 million litres of product. This suggests that the recent tank car design improvements alone are insufficient to fully mitigate the risk of adverse consequences resulting from derailments involving DGs, particularly at this speed.
While other factors, such as the integrity of the track structure, play a role, there is a clear relationship between train speed and adverse outcome when large quantities of DGs are involved. While MO-03 was a reasonable initial attempt to mitigate risk by managing train speed in consideration of a train’s risk profile, this may not be sufficient in all cases.
Train speed is one of the primary factors that contributes to the severity of a derailment. However, other factors such as train length, train weight, the position of the first car(s) derailed, the position of the cars in the train and tank car design also play a role. In order to reduce the frequency of these accidents and the commensurate risk to the public, property and the environment, Transport Canada should further review and modify key train speeds, as appropriate, based on various train risk profiles while also considering other factors that influence the severity of a derailment.
The TSB would appreciate being advised of TC’s position on this issue, and what action, if any, will be taken in this regard. Upon completion of the investigations into occurrences R20W0025 and R20W0031, the Board will release its investigation reports.
Original signed by
- Associate Administrator for Railroad Safety, Chief Safety Officer, Federal Railroad Administration (FRA)
- Assistant Vice President, Safety and Sustainability, Canadian Pacific Railway
- Assistant Vice President, Safety, Canadian National Railway
- Senior Director, Operations and Regulatory Affairs, Railway Association of Canada
Appendix A – Other derailments since 2015 that involved petroleum crude oil
|Location||Gladwick, ON||Gogama, ON||St. Lazare, MB||Barwick, ON||Near Guernsey, SK||Guernsey, SK||Emo, ON|
|Time of derailment||2335 EST||0242 EST||0231 CST||1830 EDT||0010 CST||0615 CST||2036 CST|
|Temperature at time of derailment||−31° C||−9° C||−27° C||10° C||−19° C||−18° C||−27° C|
|Subdivision||Ruel||Ruel||Rivers||Fort Frances||Sutherland||Sutherland||Fort Frances|
|Number of locomotives (of which, distributed power locomotives)||2||2||3 (1)||3 (1)||2 (1)||2 (1)||3 (1)|
|Tonnage||14 355||13 497||15 990||14 317||14 217||14 896||18 103|
|Occupancy control system (OCS)/ centralized traffic control (CTC)||CTC||CTC||CTC||CTC||OCS||OCS||CTC|
|Number of cars derailed||29||39||37||8||34||32||31|
|Number of DG tank cars derailed||29||39||37||6||33||32||27|
|Tank car type||CPC 1232||CPC 1232||DOT 117R||DOT 117R||
|Product involved||Petroleum crude oil||Petroleum crude oil||Petroleum crude oil||Petroleum crude oil||Petroleum crude oil||Petroleum crude oil||Petroleum crude oil|
|Number of tank cars that released product||19||33||14||0||23||27||5|
|Product released (litres)||1.7 million||2.6 million||820 000||0||1.5 million||1.6 million||210 000|
|Cause||Broken joint bars||Broken rail in a joint||Broken joint bars||Wide gauge (track)||Suspected broken rail||Suspected broken rail||Track infra-structure|