Rail Safety Advisory Letter 12/14

Braking analysis and bus speed approaching crossings

200 Promenade du Portage
4th Floor
Gatineau, Quebec
K1A 1K8

617-12/14
R13T0192

24 September 2014

His Worship Jim Watson
Mayor, City of Ottawa
110 Laurier Avenue West
Ottawa, Ontario
K1P 1J1

Dear Mayor Watson:

Subject:
Rail Safety Advisory Letter 12/14
Braking analysis and bus speed approaching crossings

At 0832 EDT on 18 September 2013, westward VIA passenger train No. 51 (the train) departed Ottawa VIA Station on time and proceeded en route to Toronto. At 0847, OC Transpo double decker bus No. 8017 (the bus) departed OC Transpo Fallowfield Station on the OC Transpo Bus Transitway (Transitway). At 0848, while proceeding at about 47 mph, the train entered the Transitway crossing located at Mile 3.30 of VIA Rail's Smiths Falls Subdivision (the crossing) and was struck by the northbound bus. As a result of the collision, the front of the bus was sheared off. The train, consisting of 1 locomotive and 4 passenger coaches, derailed but remained upright. Among the bus occupants, there were 6 fatalities, 8 serious injuries and approximately 25 minor injuries. No VIA crew members or passengers were injured.

The Smiths Falls Subdivision consists of single main track that extends from near the Ottawa VIA Station (Mile 0.0) to Smiths Falls, Ontario (Mile 34.40). From Monday to Friday, up to 21 passenger trains and 2 freight trains operate over the crossing each day. The authorized train speed in the vicinity of the crossing is up to 100 mph. However, trains depart VIA's Fallowfield Station at 10 to 15 mph and VIA trains arriving at the station are slowing to stop.

The Transitway is a 2-lane asphalt road that is restricted to transit (bus) traffic. Transitway traffic comprises about 1000 buses per weekday. From the OC Transpo Fallowfield Station, the Transitway extends for 812 feet (247.5 m) eastward towards Woodroffe Avenue. From that point, the Transitway transitions into a left-hand curve (in the direction of travel) that turns northward where it runs parallel and adjacent to Woodroffe Avenue (see Appendix 1). From the stop sign at Fallowfield Station, the roadway speed limit at the time of the accident was 60 km/h up to just north of the crossing, where the speed limit changed to 90 km/h.  Since the accident, the roadway speed approaching the crossing has been reduced to 50 km/h.

The crossing traverses the Transitway at a 50-degree angle. It is equipped with Automatic Warning Device (AWD) protection that includes flashing lights, bells, gates and constant warning time track circuits. At the time of the accident, the crossing protection was operating as intended with no malfunctions. The gates were horizontal for 26 seconds prior to impact.

All double decker buses at OC Transpo were designed and manufactured by Alexander Dennis Limited (ADL) in the United Kingdom. The bus was an Enviro 500 (E500) double decker model, manufactured in August 2012. It was delivered to OC Transpo in September 2012. A series of mandatory certification tests had been conducted to verify compliance with the Canada Motor Vehicle Safety Standards (CMVSS). Upon delivery of the bus, an Ontario Ministry of Transportation (MOT) inspection was performed on 21 September 2012 with no exceptions noted. The vehicle met or exceeded all required criteria for operation in Canada.

The bus did not have a single event recorder to store vehicle performance and operation data (i.e. black box). However, there were a number of electronic units that contained Non-Volatile-Memory (NVM). A total of 8 unitsFootnote 1 were recovered and all available data were downloaded and examined at the TSB Engineering Laboratory. The review of the recovered modules was completed by May 2014. Only the Engine Control Module (ECM) contained any information relevant to the operation of the bus just prior to the accident (see Appendix 2). While the ECM data were useful, they lacked sufficient detail to conduct a meaningful analysis. Subsequently, an examination of the bus braking system and a braking analysis were required.

Examination of the bus braking system was completed in June 2014 and determined that:

  • The bus design met or exceeded all requirements of the CMVSS 121: Air Brake System.
  • The bus was being maintained in accordance with the operator's approved maintenance program.
  • There were no reported brake defects on the occurrence bus.
  • There were no mechanical discrepancies identified that would preclude normal operation of the air brake system. When brakes were applied, the bus deceleration was within the design criteria for braking.

The braking analysis was performed to determine event timing, braking distance and amount of brake force applied to a loaded bus during the accident scenario. The analysis incorporated measurements and observations made on site immediately following the accident and detailed engineering calculations based on ECM data, brake system reaction time and brake performance charts from both the bus certification tests and manufacturer tests. This work was completed in August 2014 and the following observations and calculations were made:

  • The ECM data indicate that the initial application of the bus brakes occurred when the bus was travelling at a speed of 42 mph (67.6 km/h), which exceeded the posted speed limit of 60 km/h (37.3 mph).
  • The speed of the bus was between 4 and 4.8 mph (6.4 to 7.7 km/h) when it initially collided with the train. The bus moved a further 4.3 feet (1.3 m) in the forward direction after the initial impact.
  • The bus was 116.8 feet (35.6 m) away from the point of collision when braking was initiated.
  • ECM data indicate that full braking force was not initially applied.
  • If full braking force had been applied from the beginning of the brake application and assuming a constant deceleration of 0.6 g,Footnote 2 the stopping distance for the bus was calculated to be 112.5 feet (34.1 m).

Because the exact load on the bus at the time of the accident is not available, the actual bus load may have been greater than the load used for the CMVSS braking tests. Any additional load would also increase the stopping distance, in which case, there may not have been sufficient distance to stop the bus from the point at which the brakes were initially applied.

In order to assess the influence that speed may have had, additional calculations were performed based on the posted speed limit of 60 km/h (37.3 mph) with the following results:

  • The stopping distance for a bus travelling at the posted speed limit (60 km/h), with all other factors remaining the same, would have been 29.5 m (96.8 feet), which would be 6.1 m (20 feet) before the point of collision.
  • Even a modest increase of 7.6 km/h in excess of the posted speed limit can significantly increase the stopping distance required to bring a vehicle to a stop, particularly in emergency situations.

On 25 February 2014, the TSB issued Rail Safety Advisory Letter (RSA 01/14), entitled OC Transpo Buses Traversing Crossings with Activated AWD Protection, to the City of Ottawa. The letter indicated that it is imperative that all roadway vehicle drivers slow down when approaching any railway crossing, look both ways, be prepared to stop and yield the right-of-way to a train. The letter suggested that the City of Ottawa put appropriate measures in place to ensure that buses are able to stop safely in advance of an activated railway crossing signal.

In response to RSA 01/14, the City of Ottawa implemented the following actions:

  • On 28 February 2014, OC Transpo issued Bulletin No. 050/14, entitled Safet at Railway Crossings to all operators (drivers), transit supervisors and dispatchers. The bulletin noted that, when approaching a railway crossing, drivers are to observe posted speed limits, slow down, listen and look both ways before crossing the tracks.
  • On 02 May 2014, OC Transpo and the Amalgamated Transit Union (ATU) jointly issued a handout, entitled Railroad Crossings, Important Information for all Operators, to all drivers. Amongst other points, the handout reinforced that, when approaching a railway crossing, drivers are to observe posted speed limits, slow down, listen and look both ways before crossing the tracks.

In June 2014, the TSB conducted a number of speed tests on the Transitway from a location near the crossing. The speed test results are summarized as follows:

Date (2014) Total Vehicles < = 50 km/h 51-55 km/h 56-60 km/h 61-65 km/h 66-70 km/h + 70 km/h Total >50 km/h
17 June 73 58 10 2 2 - 1 15
18 June 254 194 37 18 4 1 - 60
19 June 152 105 31 10 3 3 - 47
25 June 191 144 27 12 2 5 1 47
Total # vehicles 670 501 >105 42 11 9 2 169

OC Transpo has taken some steps to raise driver awareness of railway crossing safety and to reinforce the need for its drivers to slow down. However, a number of drivers continue to travel in excess of the posted speed limit in the vicinity of the crossing. Engineering analysis has identified that even a modest increase in excess of the posted speed limit can significantly increase the bus stopping distance. Therefore, the City of Ottawa may wish to implement additional measures to monitor and control bus speed, particularly in the vicinity of railway crossings.

We would appreciate if you would inform us of any safety measures you plan to implement. We will take these measures into consideration as part of our ongoing investigation.

Yours sincerely,

Original signed by
Kirby Jang
Director
Investigations, Rail/Pipeline

Cc:
Kash Ram
Director General, Road Safety and Motor Vehicle Regulation
Transport Canada
 
Luc Bourdon
Director General, Rail Safety
Transport Canada
 
Kent Kirkpatrick
City Manager
City of Ottawa
 
John Manconi
General Manager, Transit Services
City of Ottawa
 
Jean Tierney
Senior Director, Safety, Security & Risk Management
VIA Rail Canada Inc
 
Marc Tessier
Director, Corporate Security & Regulatory Affairs
VIA Rail Canada Inc.
 
Nicolas Panetta
Manager, Risk Management
VIA Rail Canada Inc.
 
Colin Robertson
President & Chief Executive Officer
Alexander Dennis Limited - United Kingdom
 
Stephen Walsh
Vice-President, North America
Alexander Dennis Inc.

Background information

TSB Occurrence: R13T0192 (Class 2)

Contacts: Rob Johnston
Investigator-in-Charge
Manager, Head Office & Central Region
TSB Ottawa, ON
819-956-8736

Appendix 1 – Site diagram

Appendix 2 – Bus engine control module recorded data

PowerSpec - Sudden deceleration data report
Time (Seconds) Vehicle Speed (mph) Engine Speed (rpm) Engine Load (%) Throttle (%) Brake Status Clutch Status Cruise Status Lamp Status
-39 0 735 60.2 38.9 - - - -
-38 0 942 48.8 42.1 - - - -
-37 2 1079 65.6 81.8 - - - -
-36 4 1404 71.9 88.9 - - - -
-35 7 1760 85.2 89.0 - - - -
-34 9 1855 84.4 89.0 - - - -
-33 11 1801 85.2 89.1 - - - -
-32 13 1854 84.4 88.9 - - - -
-31 15 1849 84.4 89.1 - - - -
-30 17 1575 88.7 89.1 - - - -
-29 19 1329 93.4 89.1 - - - -
-28 20 1398 93.4 89.1 - - - -
-27 22 1495 91.0 89.1 - - - -
-26 23 1438 91.8 89.1 - - - -
-25 24 1152 99.6 89.1 - - - -
-24 25 1208 98.0 89.1 - - - -
-23 26 1254 95.7 89.1 - - - -
-22 27 1306 93.8 89.1 - - - -
-21 28 1354 93.4 89.1 - - - -
-20 30 1401 93.4 89.0 - - - -
-19 30 1444 92.2 89.1 - - - -
-18 31 1484 91.0 89.1 - - - -
-17 32 1513 89.8 89.1 - - - -
-16 33 1156 98.8 89.1 - - - -
-15 34 1184 99.6 89.1 - - - -
-14 35 1206 98.4 89.1 - - - -
-13 35 1234 96.9 89.1 - - - -
-12 36 1256 95.7 89.1 - - - -
-11 37 1275 94.9 89.1 - - - -
-10 37 1307 93.4 89.0 - - - -
-9 38 1323 85.5 83.2 - - - -
-8 39 1345 65.6 68.8 - - - -
-7 39 1359 66.4 69.4 - - - -
-6 40 1373 92.6 88.4 - - - -
-5 40 1397 92.6 88.6 - - - -
-4 41 1422 92.2 88.7 - - - -
-3 41 1444 91.4 88.8 - - - -
-2 42 1270 94.5 88.6 - - - -
-1 42 1250 0.0 0.0 - - - -
0 35 1004 0.0 0.0 On - - -
1 25 708 0.0 0.0 On - - -
2 5 659 20.3 0.0 On - - -
3 2 285 0.0 0.0 On - - On
4 0 51 0.0 0.0 On - - On
5 0 0 0.0 0.0 On - - On
6 0 0 0.0 0.0 On - - On
7 0 0 0.0 0.0 On - - On
8 0 0 0.0 0.0 On - - On
9 0 0 0.0 0.0 On - - On
10 0 0 0.0 0.0 On - - On
11 0 0 0.0 0.0 On - - On
12 0 0 0.0 0.0 - - - -
13 0 0 0.0 0.0 - - - -
14 0 0 0.0 0.0 - - - -
15 0 0 0.0 0.0 - - - -

Footnotes

Footnote 1

The units included the anti-lock braking system/anti-slip regulation (ABS/ASR) control module, the central controller, the transmission control module (TCM), the heating-ventilation and air conditioning (HVAC) system memory, the automatic fare recording Presto units, the Intelligent Vehicle Network (IVN) system, Global Positioning System (GPS) data from the City of Ottawa and the Engine Control Module (ECM).

Return to footnote 1 referrer

Footnote 2

0.6 g is the manufacturer's minimum value specified for deceleration (1g is equal to an acceleration / deceleration of 32.1 ft/s2 or 9.8 m/s2).

Return to footnote 2 referrer