DOT-111 tank car

From Wikipedia, the free encyclopedia - View original article

 
  (Redirected from DOT-111)
Jump to: navigation, search
A DOT-111 tank car, specification 111A100W1, constructed by fusion welding carbon steel. This car has a capacity of 30,110 US gallons (113,979 L), a test pressure of 100 psi (690 kPa), a tare weight of 65,000 pounds (29,500 kg) and a load limit of 198,000 pounds (89,800 kg).

In rail transport, the U.S. DOT-111 tank car, also known as the CTC-111A in Canada,[1] is a type of non-pressure tank car in common use in North America. Tanks built to this specification must be circular in cross section, with elliptical, formed heads set convex outward.[2] They have a minimum plate thickness of 716 inches (11.1 mm)[3] and a maximum capacity of 34,500 US gallons (131,000 L; 28,700 imp gal).[4] Tanks may be constructed from carbon steel, aluminum alloy, high alloy steel or nickel plate steel[5] by fusion welding.[6]

A damaged DOT-111A tank car. Note the AAR Type E double shelf coupler required for transporting dangerous goods.

Up to 80% of the Canadian fleet,[1] and 69% of U.S. rail tank cars are DOT-111 type.[3] DOT-111A cars are equipped with AAR Type E top and bottom shelf Janney couplers designed to maintain vertical alignment to prevent couplers from overriding and puncturing the tank end frames. Many of these transport a wide spectrum of dangerous goods, including 40,000 cars in dedicated service carrying 219,000 car loads of ethanol fuel annually in the U.S.[3]

Hydraulic fracturing of new wells in the shale oil fields in the interior of North America has rapidly increased use of DOT-111 cars to transport crude oil to existing refineries along the coasts.[7] The Montreal, Maine and Atlantic Railway runaway train in the Lac-Mégantic derailment of 2013 was made up of 72 of these cars,[8][9] some of which ruptured, releasing explosively[10] their cargo of Bakken formation light crude oil, resulting in a large fire and mass casualty event.

Two different 111A100W1 specification tank cars, both with 263,000-pound (119,000 kg) gross rail load. On the left is a 27,399-US-gallon (103,716 L) capacity tanker with a load limit of 196,500 pounds (89,100 kg), making it suitable for low specific gravity liquids. On the right, a lighter, smaller 16,640-US-gallon (62,989 L) capacity tanker has a higher load limit of 204,300 pounds (92,700 kg). It is stenciled and placarded for 50% sodium hydroxide aqueous solution, which has a specific gravity of 1.5. This car is also equipped with an insulating jacket and external heating pipes to melt frozen contents if necessary.

Construction[edit]

Schematic cutaway view (not to scale) of end of tank car showing major components.

The DOT-111 tank cars are constructed with a draft sill design. Draft sills incorporate the draft gear behind each coupler that is designed to transfer longitudinal draft (tension) and buff (compression) forces throughout the length of a train. The draft sills are attached to steel pads that are attached to the tank. If the cars do not incorporate a continuous center sill extending the entire length of the car, the two draft sills at each end are referred to as stub sills, and the tank carries draft forces between couplers. In this case, reinforcing bars may be extended underneath the tank between the draft sills. Body bolsters and their associated body bolster pads centered above the railcar trucks support the tank and protect it against lateral forces. The draft sill center plate serves as the attachment point between the tank car body and the truck assembly. (See schematic cutaway at right.)[11]

Draft sill structural and weld details

The body bolster pads and front sill pads are attached to the tank with fillet welds. At the rear edge of the front sill pad, a butt weld attaches the front sill pad to the body bolster pad and to the fillet weld attaching the body bolster pad to the tank shell. Fillet welds at the interior and exterior sides of the head brace attach the head brace to the front sill pad, and an exterior fillet weld attaches the head brace to the draft sill. To the rear of the head brace, the draft sill is welded to the front sill pad, body bolster pad, and reinforcing bars.[11]

Because rail cars have no front or rear, for descriptive purposes, the ends of the cars are designated "A" and "B." The B end of the car is the end equipped with the wheel used to manually set the car's hand brakes. The end without the brake wheel is the A end. As trains are assembled, either end of a tank car may be placed in the front or rear position. The tank shells are constructed of several rings welded together, with six rings in a typical configuration. By convention, ring-1 is at the A end, and if there are six rings, ring-6 is at the B end.[11] The tank rings can be welded in a "straight barrel" configuration, or with a "slope bottom" sloping down to a bottom outlet valve at the center of the tank.[12]

Diagram of a DOT-111J100W1 tank car with an insulating jacket and external heating coils. It has a capacity of 20,000 US gallons (76,000 L; 17,000 imp gal).

Regulations[edit]

The relevant US regulatory framework is found at 49 CFR Part 179. An overview of "49 CFR Part 179 - SPECIFICATIONS FOR TANK CARS" is available online.[13] while the Means of Containment of the Transport of Dangerous Goods Regulations of Canada is found in Part 5.[14] The US regulations call for the employment DOT-xxx containment standards, where 'x' substitutes to a numeral between 0 and 9, while the Canadian TDG Regulations have latterly a CSA/CGSB-xx.xxx container standard nomenclature, although as noted by Powers,[1] the DOT-111 standard seems to apply in Canada.

A 2013 Senate of Canada committee report proposed mandatory minimum insurance for rail companies.[15] Currently the railway industry lags the pipeline industry in value of mandatory insurance coverage, to a ratio of 1:40.[15]

Railway operators are not required to inform Canadian municipalities about hazardous goods in transit.[16] The 2013 Senate committee (see above) recommended the creation of an online database with information on spills and other incidents from rail cars.[15]

DOT-112 tank cars and DOT-114 tank cars have been required since 1979 under Regulation SOR/79-101 of the Canada Transportation Act for the transportation of gases such as propane, butane, or vinyl chloride.[17] Transportation Safety Board of Canada Railway Investigation Report R94T0029[18] section 1.13.1 documents DOT-112 tank car and DOT-114 tank car standards: the DOT-111 tank "cars are not considered to provide the same degree of derailment protection against loss of product as the classification 112 and 114 cars, designed to carry flammable gases." DOT-111 tank cars may have been employed in trains such as those of the Lac-Mégantic derailment because crude oil is largely not a gaseous product at standard temperature and pressure.

Accident investigations[edit]

A report on "The State of Rail Safety in Canada" was commissioned by Transport Canada in 2007.[19] The report contains a 10-year statistical examination of its subject. Section 6 is entitled "Accidents involving dangerous goods". A formal review of the Railway Safety Act was empanelled by the Minister in February 2007.[20] The review, which was tabled in Parliament later that year, has a different take on the subject.

Completed[edit]

An older DOT-111 tank car manufactured in 1967 shown as it appeared in 1996. This car was equipped with an insulating jacket and had a capacity of 20,670 US gallons (78,200 l; 17,210 imp gal).

During a number of accident investigations over a period of years, the U.S. National Transportation Safety Board has noted that DOT-111 tank cars have a high incidence of tank failures during accidents.[3] Previous NTSB investigations that identified the poor performance of DOT-111 tank cars in collisions include a May 1991 safety study as well as NTSB investigations of a June 30, 1992, derailment in Superior, Wisconsin;[21] a February 9, 2003, derailment in Tamaroa, Illinois;[22] and an October 20, 2006, derailment of an ethanol unit train in New Brighton, Pennsylvania.[23] In addition, on February 6, 2011, the Federal Railroad Administration (FRA) investigated the derailment of a unit train of DOT-111 tank cars loaded with ethanol in Arcadia, Ohio, which released about 786,000 US gallons (2,980,000 l; 654,000 imp gal) of product.[24] The Transportation Safety Board of Canada also noted that this car's design was flawed resulting in a "high incidence of tank integrity failure" during accidents.[1]

In Railway Investigation Report R94T0029,[18] the Transportation Safety Board of Canada (TSBC) investigated a derailment incident near Westree, Ontario which occurred on 30 January 1994. They cited report NTSB/SS-91/01 which questioned "the safety of ... 111A tank cars." Furthermore, "... report [NTSB/SS-91/01] determined that this classification of tank car has a high incidence of tank integrity failure when involved in accidents and that certain hazardous materials are transported in these tank cars even though better protected cars (less liable to release the transported product when involved in accidents) are available." The TSBC instituted "Amendment Schedule No. 21 to the Transportation of Dangerous Goods Regulations", which mandated "the use of revised tank car standard CAN/CGSB 43.147-94. This standard restricts the use of 111A tank cars, and removes over 80 dangerous goods previously authorized for transportation in Class 111 cars." The status of Amendment Schedule No. 21 is unknown, as of August 2013, although the Standards Council of Canada reports that CAN/CGSB 43.147-94 was superseded by CAN/CGSB-43.147-97.[25] The updated standard is available through the Canadian General Standards Board.[26]

Approximately 230,000 litres (51,000 gallons) of sulphuric acid was released, causing environmental damage, on 21 January 1995 near Gouin, Quebec. "Unit trains of sulphuric acid were introduced into service in the 1950s. Sulphuric acid cars are usually loaded to the maximum allowable car weights. Loaded unit sulphur trains, with every car carrying maximum loading, present a severe concentration of mass over a relatively short length of track."[27] The 11 rail cars that released product were standard series CTC-111A tank cars. The derailment was caused by gauge loss, and the number of defective ties north of the derailment area likely exceeded Canadian National's (CN) maintenance standard. Transport Canada determined that a retrofit of the top fittings of all Class 111A cars would exceed one billion dollars. The estimated cost of the Lac-Megantic derailment environmental cleanup (only) is one quarter of a billion dollars.

In Report Number R96M0011,[28] the Transportation Safety Board of Canada (TSBC) investigated an occurrence near River Glade, New Brunswick which occurred on 11 March 1996. The 1996 report concluded that "Class 111A tank cars are more susceptible to release product upon derailment and impact than pressure tank cars, and yet there are a number of toxic and volatile liquids that are still permitted to be carried in minimum standard Class 111A tank cars." The report makes no recommendation to upgrade or limit the use of Class 111A tank cars.

An investigative report published 3 August 2013 by the Brandon Sun listed 10 railway derailments in the area over the past decade. Derailments caused no injuries over that period.[29]

On 2 May 2002, a train collided with a transport truck at the Firdale, Manitoba CN crossing. The derailed equipment included five tank cars carrying dangerous goods. During the derailment, four of the tank cars sustained multiple punctures and released their products. The products ignited and a large fire engulfed the derailed cars.[30]

The National Research Council was commissioned via the Hazardous Materials Transportation Uniform Safety Act (1990) by the Federal Railroad Administration to write an impartial report on "(1) the railroad tank car design process, including specifications development, design approval, repair process approval, repair accountability, and the process by which designs and repairs are presented, weighed, and evaluated, and, (2) railroad tank car design criteria, including whether head shields should be installed on all tank cars that carry hazardous materials." It is entitled "Ensuring Railroad Tank Car Safety"[31] and available as ISBN 0-309-05518-0.

Ongoing[edit]

Lac-Mégantic derailment[edit]

Questions have been raised by the Transportation Safety Board of Canada investigators regarding the contents of the Lac-Mégantic train, because the "crude oil acted in ‘abnormal’ way".[32] The Enbridge corporation "has complained numerous times to U.S. regulators that Bakken’s crude oil is volatile".[32] This situation is similar to those that were detailed 12 years earlier in the Hazardous Materials Accident Report on the 'Rupture of a Railroad Tank Car Containing Hazardous Waste Near Clymers, Indiana'.[33]

One issue raised by the Lac-Mégantic derailment, and substantiated by Enbridge complaints to the US regulator,[32] is whether the DOT-111 tank car is the appropriate vessel to contain Bakken crude oil, given that the substance in question is associated with a notable volatility. A wider margin for safety would seem to be provided by the DOT 112 tank car. The explosive release[34] of Bakken formation crude seen in the Lac-Mégantic derailment begs the question why this material is not classed as a HAZMAT Class 1 Explosives material.

The US Federal Railroad Administration moved on 8 August 2013 to tighten standards for shipments of crude oil from the Bakken formation (and other?) fields that contain volatile and/or corrosive chemicals, such as may issue from the hydraulic fracturing process.[35] Crude oil is classed as HAZMAT Class 3 Flammable Liquids.[36] The US regulator had ignored until 8 August 2013 the corrosive contents of Bakken formation crude oil. The immiscibility of crude oil and acid causes the acid to settle to the bottom of a container,[35] and this may add to the corrosion. Given that a substantial fraction of rail stock is of DOT-111 type,[1] the shipment of Bakken formation crude oil risks becoming more expensive over the medium term as the DOT-112 tank cars necessary for shipment will initially be relatively scarce.

Curiously, Federal Railroad Administration official Thomas J. Herrmann considers some crude oil not to be flammable.[35] Hazardous materials standards, such as the HAZMAT Class 3 Flammable Liquids standard are notoriously difficult to read. Herrmann, who wrote a letter[37] to the American Petroleum Institute on 29 July 2013, stated that "It is critical that shippers determine the proper classification of the crude oil".[38] The Herrmann letter broadcasts the failure of the FRA to regulate adequately, with the result that "one shipper had put the highest degree of hazardous crude into a rail tanker suitable only for the lowest degree".[38] Herrmann seems confused, because the American Petroleum Institute lobby may or may not communicate with, or represent, the shippers of crude oil. For example, in the case of the Lac-Mégantic derailment, the lessor of the DOT-111 tank cars World Fuel Services[39] is a broker organization and in no way required to be members of the API lobby, so the effect of the letter to the API may be nil.

Hydrogen sulfide (H2S, sour gas), a gas which is toxic to humans and flammable, has been detected as well in Bakken crude by Enbridge.[40] The academic community commented in 2011 that increased concentration of H2S was observed in the field and presented challenges such as "health and environmental risks, corrosion of wellbore, added expense with regard to materials handling and pipeline equipment, and additional refinement requirements".[41] Holubnyak et al. write, further, that Bakken crude "may become soured through current oil field practices". At issue in the Lac-Mégantic derailment, then, is whether World Fuel Services and other defendants ought to have been aware of this two-year old research when they ordered the DOT-111 tank cars (which were already in 2012 acknowledged by the US NTSB regulator to be deficient for these purposes[40]) to be loaded on the Lac-Mégantic train. The continued misuse as from 13 August 2013 of DOT-111 tank cars to ship Bakken formation petroleum may well liable for treble damages in US courts, because the behaviour is now known to be wanton.

The Lac-Mégantic runaway train had earlier passed through Toronto on its way from the Bakken[disambiguation needed] fields of Dakota. A Canadian National employee said that roughly 10% of shipments through Toronto contain hazardous materials that are often stored on DOT-111 tank cars, but that only first responders have access to HAZMAT shipment information.[42]

New construction standards[edit]

Derailment in Cherry Valley, Illinois. Thirteen DOT-111 tank cars lost about 324,000 US gallons (1,230,000 L; 270,000 imp gal) of ethanol contaminating a tributary of the Rock River resulting in one of the largest fish kills in Illinois history.

As a result of an accident in Cherry Valley, Illinois, in 2009, the Association of American Railroads studied several options for increasing the crashworthiness of DOT-111 tank car designs and published new construction standards in a Casualty Prevention Circular, with the intent to revise the AAR Manual for Standards and Recommended Practices for tank cars that are used to transport ethanol and crude oil. Beginning on October 1, 2011, the new AAR standard for DOT-111 tank cars requires tank heads and shells to be constructed of thicker steel. The new specification also requires that heads and shells be constructed of normalized steel, and in all cases 12-inch (12.7 mm) thick half head shields must be provided. The AAR has also mandated a more robust housing or rollover skid for protection of top fittings.[3] The new standards only apply to newly manufactured cars; there is no requirement to retrofit, repurpose, or retire existing DOT-111A cars built to the older design. The NTSB has called that design "inadequate," noting the older cars are "subject to damage and catastrophic loss of hazardous materials."[24]

Had the tank cars in use for the Lac-Megantic derailment train been instead of DOT-112 tank car standard, they could have borne (a) a pool fire for 100 minutes; and (b) a torch fire for 30 minutes, and could have been able to withstand a coupler-to-head impact at up to 28.968 km/h.[43] The consignor of the shipment involved in the Lac-Megantic derailment, World Fuel Services corporation, was responsible for leasing the DOT-111A tank cars.[39]

See also[edit]

References[edit]

  1. ^ a b c d e Powers, Lucas (Jul 9, 2013). "Safety rules lag as oil transport by train rises - British Columbia". CBC News. Retrieved 10 July 2013. 
  2. ^ 49 C.F.R. 179.200-3
  3. ^ a b c d e Stancil, Paul L. (2012-02-17). "DOT-111 Tank Car Design". National Transportation Safety Board, Office of Railroad, Pipeline and Hazardous Materials Safety. Retrieved 9 July 2013. 
  4. ^ "Module 3: Transportation and Transfer of Ethanol-Blended Fuels". Commonwealth of Massachusetts, Executive Office of Public Safety and Security, also available at archive.org. Retrieved 10 July 2013. 
  5. ^ 49 C.F.R. 179.200-7
  6. ^ 49 C.F.R. 179.200-10
  7. ^ Philips. Matthew (2013-07-10). "Will the Quebec Accident Derail the Oil Train Boom?". Bloomberg Businessweek. Retrieved 11 July 2013. "...railroads have beaten pipelines to the punch by connecting refining hubs around the U.S. to the new hot-spots of oil production in such remote places as North Dakota, Oklahoma, and West Texas. In the first three months of 2013, trains moved more than 97,000 carloads of crude in the U.S.—900 percent more than in all of 2008." 
  8. ^ Ha, Tu Thanh (2013-07-08). "Rail cars like those in Lac-Mégantic disaster are prone to puncturing". The Globe and Mail. Retrieved 10 July 2013. "Surviving cars that were pulled out of the blast had stenciled markings indicating that they were a type of steel car called DOT-111A in the United States and CTC-111A in Canada. ...in the Lac-Mégantic tragedy...an out-of-control 72-car train barrelled downhill into the town centre and derailed." 
  9. ^ "Lac-Mégantic : la sécurité du type de wagons déjà mise en cause" (in French). Radio-Canada. July 8, 2013. Retrieved July 8, 2013. 
  10. ^ CBC "Lac-Mégantic marks 1 month since deadly train explosion" story
  11. ^ a b c "Derailment of CN Freight Train U70691-18 With Subsequent Hazardous Materials Release and Fire; Cherry Valley, Illinois; June 19, 2009". NTSB/RAR-12/01. National Transportation Safety Board. February 14, 2012. Retrieved 12 July 2013. 
  12. ^ "SPECIFICATIONS DOT 111A100W1 ETHANOL/METHANOL". American Railcar Leasing. Retrieved 12 July 2013. 
  13. ^ Overview of, and links to, 49 CFR Part 179
  14. ^ Text of Part 5 of the TDG Part 5
  15. ^ a b c postmedia: "Senate committee proposes mandatory minimum insurance for rail companies after Lac Megantic"
  16. ^ Sudbury Star on Lac-Megantic and rail safety 1 Aug 2013
  17. ^ Text of Canadian Regulation SOR-79-101
  18. ^ a b TSBC Report R94T0029
  19. ^ [http%3A%2F%2Fwww.tc.gc.ca%2Fmedia%2Fdocuments%2Frailsafety%2Fcpcs.pdf PDF copy of "The State of Rail Safety in Canada"]
  20. ^ RSA Review
  21. ^ Derailment of Burlington Northern Freight Train No. 01-142-30 and Release of Hazardous Materials in the Town of Superior, Wisconsin, June 30, 1992, Hazardous Materials Accident Report NTSB/HZM-94/01. Washington, DC: National Transportation Safety Board. 1994 
  22. ^ Derailment of Canadian National Freight Train M33371 and Subsequent Release of Hazardous Materials in Tamaroa, Illinois, February 9, 2003, Accident Report NTSB/RAR-05/01. Washington, DC: National Transportation Safety Board. 2005 
  23. ^ "Railroad Accident Report: RAR-08-02". National Transportation Safety Board. October 20, 2006. Retrieved 10 July 2013. 
  24. ^ a b Hersman, Deborah A.P. (March 2, 2012). Safety Recommendation R-12-005-008. National Transportation Safety Board. Retrieved 10 July 2013 
  25. ^ SCC documentation on CAN/CGSB 43.147-94
  26. ^ http://www.tc.gc.ca/eng/tdg/moc-railcar-cgsb43147-294.html
  27. ^ Text of TSBC r95d0016 report
  28. ^ TSBC Report Number R96M0011
  29. ^ "Railways refuse to reveal toxic cargo"
  30. ^ Link to Firdale, Manitoba Railway Investigation Report R02W0063
  31. ^ Ensuring Railroad Tank Car Safety
  32. ^ a b c Montreal Gazette, 2013 08 02 report by Christopher Curtis
  33. ^ NTSB/HZM-01/01
  34. ^ CBC "Lac-Mégantic marks 1 month since deadly train explosion" story 8 Aug 2013
  35. ^ a b c "Officials Tighten Crude-Shipping Standards" Morris and Gold authors, also see Globe and Mail reprint on 8 August 2013
  36. ^ environmentalchemistry.com website, search under "Petroleum crude oil"
  37. ^ FRA Herrmann letter to API 29 July 2013
  38. ^ a b William Marsden, Postmedia News report 9 August 2013 "Crude oil shipped in unsafe rail cars, U.S. agency claims"
  39. ^ a b Kovac and Sparks, in Montreal Gazette 11 Aug 2013
  40. ^ a b Bloomberg report NP 13 August
  41. ^ Holubnyak et al, SPE 141434-MS
  42. ^ "Downsview man wants more info about dangerous freight" 11 August 2013 CBC story
  43. ^ Text of SOR/79-101

 This article incorporates public domain material from the National Transportation Safety Board document "Unclassified Safety Recommendation R-12-005-008, March 2, 2012".
 This article incorporates public domain material from the National Transportation Safety Board document "DOT-111 Tank Car Design".
 This article incorporates public domain material from the National Transportation Safety Board document "Derailment of CN Freight Train U70691-18 With Subsequent Hazardous Materials Release and Fire; Cherry Valley, Illinois; June 19, 2009".