dave1905 Posted February 22, 2015 Share Posted February 22, 2015 In every accident they research what was the cause. harmonic rocking has not been the cause in any of the previous accidents. There are thousands of unit trains of tank cars that operate every year. Some of them carry crude oil. Harmonic rocking is not a problem in the trains that are not oil trains either. Link to post Share on other sites More sharing options...
Talltim Posted February 22, 2015 Share Posted February 22, 2015 Harmonic rocking may be related to to Cyclic top, but it is not the same, Harmonic rocking is, AFAIK, side to side motion normally caused by staggered rail joints. (Which you don't get in the UK) Cylic top is caused by dips in the track that happen to come at the same frequency as the rebound in the suspension. This is dependent on train speed, suspension setup, vehicle weight and the distance between dips and can occur in CWR. It's been a while since I read the RAIB report but I think I remember it containing a far better description of the process. http://www.raib.gov.uk/publications/investigation_reports/reports_2014/report202014.cfm Link to post Share on other sites More sharing options...
Ohmisterporter Posted February 22, 2015 Share Posted February 22, 2015 As someone who has never seen inside a tank wagon can I ask if there are baffles across the tank or are they simply an empty vessel? Pictures I have seen of vacuum imploding tanks would suggest the latter. Link to post Share on other sites More sharing options...
Brian Harrap Posted February 22, 2015 Share Posted February 22, 2015 As someone who has never seen inside a tank wagon can I ask if there are baffles across the tank or are they simply an empty vessel? Pictures I have seen of vacuum imploding tanks would suggest the latter. Yes, I'd like to know about that. Brian Link to post Share on other sites More sharing options...
peach james Posted February 22, 2015 Share Posted February 22, 2015 One baffle will 1/4th the forces, 2 will give you 1/9th the forces. (Free Surface Effect) Link to post Share on other sites More sharing options...
highpeak Posted February 22, 2015 Share Posted February 22, 2015 Quote from an AAR guide to tank cars: "Note: Unlike highway cargo tanks, tank car compartments are not constructed by applying interior walls within a single tank. Further, unlike some cargo tanks, tank carsdo not have interior baffles to control lading surges." http://www.bnsfhazmat.com/refdocs/1326686674.pdf And once again, since there seems to have been an invisible ink problem, I am NOT suggesting that either harmonic rock off or surging of the lading was the cause of this derailment. Comment on railroad.net suggests that the problem might have been related to instability of the road bed. Reuters is reporting that CSX has informed the state of a change in the routing of these trains and speculation on Railroad.net is that the detour may be permanent. http://www.reuters.com/article/2015/02/19/us-usa-train-derailment-csx-idUSKBN0LN1SX20150219 Link to post Share on other sites More sharing options...
dullsteamer Posted February 23, 2015 Share Posted February 23, 2015 I agree that cars 'usually' derail only when on the move. However, there have been occasions when cars have derailed when standing in yards, where the state of the ties and fastenings has been such that they have failed under the weight of the cars. Been there, done that, had to call out the rerailing gang. Cheers, Mark. Link to post Share on other sites More sharing options...
Andy Reichert Posted February 23, 2015 Share Posted February 23, 2015 http://www.ksby.com/news/fuel-hauling-trains-could-derail-at-10-a-year/ Apparently statistics indicate a considerable number of derailments yet to come. Link to post Share on other sites More sharing options...
RMweb Gold The Stationmaster Posted February 23, 2015 RMweb Gold Share Posted February 23, 2015 http://www.ksby.com/news/fuel-hauling-trains-could-derail-at-10-a-year/ Apparently statistics indicate a considerable number of derailments yet to come. An interesting approach to safety management. First decide what you wish to impose as a constructional standard for rail vehicles then find some numbers to support your proposal. Not necessarily an unusual approach but it would be fascinating to know why they have adopted this approach rather than the somewhat more positive one of proposing action to prevent, or greatly reduce, their forecast number of derailments. After all the safest way of stopping a loaded tank car from bursting into flames is not to derail it or hit it too hard. Link to post Share on other sites More sharing options...
Talltim Posted February 23, 2015 Share Posted February 23, 2015 And once again, since there seems to have been an invisible ink problem, I am NOT suggesting that either harmonic rock off or surging of the lading was the cause of this derailment. Sorry, I didn't think you were saying they were, just trying to explain the difference between harmonic rocking and cyclic top. Link to post Share on other sites More sharing options...
dave1905 Posted February 23, 2015 Share Posted February 23, 2015 The causes of the derailments have been all over the map, so there is no one target to shoot at. Common theme is that the type 111 tank car is not robust enough. New designs have been proposed, but not yet adopted. I see the DOT press release as an effort to pressure those holding up the adoption of the new tank car standards to get off center and formally adopt the new standards. Part of the problem is the commodity, the North Dakota crude reacts differently than most other crudes, part of it is the cars, the less robust cars allow what would be a minor incident with stronger cars to become a major incident. The major railroads have beefed up their securement rules, especially for "key" trains (hazmat trains), have lowered train speeds and increased inspections of track. Link to post Share on other sites More sharing options...
w124bob Posted February 23, 2015 Share Posted February 23, 2015 Many years ago I actually witnessed a loco(almost new cl56) derail when stationary. The incident occurred whilst the driver and I went for a brew , we'd had several days of hard frost followed by a thaw and rain, throw in rotten sleepers, a loco weighing far more than the usual cl20's, rusty 100year old rail and chairs just gave out . Am I correct in thinking that most tank cars are not owned by the rail companies or shippers so replacement would fall to Procor etc. Link to post Share on other sites More sharing options...
Glorious NSE Posted February 23, 2015 Share Posted February 23, 2015 Whilst I agree things can potentially derail whilst standing still, i'm not convinced that it'd cause spontaneous combustion! Am I correct in thinking that most tank cars are not owned by the rail companies or shippers so replacement would fall to Procor etc. Most are owned by leasing companies and leased to the shipper.Some railroads have been proactive in trying to promote change however, BNSF has bucked modern historical trend and has reportedly ordered a fleet of their own higher spec cars, they have also introduced surcharges on the use of lower spec cars in this traffic. Other railroads may do (or may have done?) similar things.These though were supposedly the higher spec cars - as Dave says, better cars aren't going to prevent a given incident from happening, but they should mean that smaller scale derailments are much less spectacular. Link to post Share on other sites More sharing options...
Adrian Wintle Posted February 23, 2015 Share Posted February 23, 2015 Am I correct in thinking that most tank cars are not owned by the rail companies or shippers so replacement would fall to Procor etc. That is correct. I don't think that railrads own tank cars these days except for their own use. Here is an oil train on the CN main line from Dec 2013. Note that all the cars are new and have end guards, but there is no trailing barrier car. And here is one from June 2014. There is a trailing barrier car. Adrian Link to post Share on other sites More sharing options...
Glorious NSE Posted February 23, 2015 Share Posted February 23, 2015 Interesting article... http://www.railwayage.com/index.php/safety/oil-train-mishaps-reveal-tank-car-strengths-and-limitations.html?channel=59 Link to post Share on other sites More sharing options...
Adrian Wintle Posted February 23, 2015 Share Posted February 23, 2015 Interesting article... http://www.railwayage.com/index.php/safety/oil-train-mishaps-reveal-tank-car-strengths-and-limitations.html?channel=59 Particularly the bit about not separating out the volatile gas before shipping the oil because there is no ready market for the gas in North Dakota. It suggests a significant financial incentive to ship the untreated crude. Adrian Link to post Share on other sites More sharing options...
highpeak Posted February 23, 2015 Share Posted February 23, 2015 The blog I linked to earlier in the thread http://http://www.desmogblog.com/2014/12/11/north-dakota-s-meaningless-new-regulations-will-keep-bomb-trains-rolling included an extract from new regulations published by the North Dakota Industrial Commission in December last year that prohibited the blending of crude with natural gas liquids, suggesting that in the past NGLs were not only not being stripped from the oil but were in fact being added. That blog and the Railway Age article Martyn linked to would seem to suggest that the odds are pretty high of a derailment at speed turning into a disaster well beyond what you would expect from a crude oil spill. Link to post Share on other sites More sharing options...
Talltim Posted February 24, 2015 Share Posted February 24, 2015 That is correct. I don't think that railrads own tank cars these days except for their own use. Here is an oil train on the CN main line from Dec 2013. Note that all the cars are new and have end guards, but there is no trailing barrier car. DSCN1617s.jpg DSCN1621s.jpg DSCN1626s.jpg DSCN1628s.jpg And here is one from June 2014. There is a trailing barrier car. DSCN1814s.jpg DSCN1815s.jpg DSCN1816s.jpg Adrian Is it likely that the train without the barrier cars is empty? Link to post Share on other sites More sharing options...
dave1905 Posted February 24, 2015 Share Posted February 24, 2015 No. It has no "cover" (barrier) because none is required. There are no engines or caboose coupled to the rear of the train, so no cover is required. The cover is to separate engines or cabooses from the train, no engines, no caboose, nothing to separate. Link to post Share on other sites More sharing options...
Adrian Wintle Posted February 24, 2015 Share Posted February 24, 2015 Is it likely that the train without the barrier cars is empty? It is an eastbound, so no, it is a full train. As Dave says, there is no requirement for a barrier car there but they do frequently have one, presumably to avoid having to shunt the barrier car to the other end for the return trip. In the case of the second train, it was a cut of cars attached to the back of a manifest freight and had a barrier car on either end of the cut (which was about half the train). In the first photo you can just see the non-tank cars (covered gons) ahead of the leading barrier car. It would appear that there was effectively a fixed rake of tank cars with a barrier on each end. Adrian Link to post Share on other sites More sharing options...
Gerald Henriksen Posted March 6, 2015 Share Posted March 6, 2015 And we have another one: http://www.thestar.com/news/world/2015/03/05/freight-train-with-crude-oil-derails-catches-fire-in-illinois.html Link to post Share on other sites More sharing options...
shortliner Posted March 7, 2015 Share Posted March 7, 2015 Without going all the way back through this to see if it has been posted - this just in from a mate in Canada Link to post Share on other sites More sharing options...
dave1905 Posted March 7, 2015 Share Posted March 7, 2015 That's the clearest picture I've seen. POD right at a switch. Link to post Share on other sites More sharing options...
Gerald Henriksen Posted March 7, 2015 Share Posted March 7, 2015 And yet another today: http://www.cbc.ca/news/canada/sudbury/train-carrying-crude-oil-derails-near-gogama-ont-1.2985703 Link to post Share on other sites More sharing options...
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