Readers’ Forum
OPINION
Tanks have a round cross-section so that they can handle some pressure before the blow-out valve pops off. This allows time to control the situation before it gets worse. An egg-shaped cross-section would distort and cause a container breach under moderate pressure. Modern tank cars have received recent up- grades in valve safety, wall thickness and the reliability of blow- out valves. It’s better to have a blow-out valve pop off and result in a small torch than it is to have a BLEVE — the term used for a boiling liquid expanding vapour explosion. The slow trains that we have now are due to line congestion (think Whitemud Drive in the mornings, if you live in Edmonton). I routinely see trains moving around 80 kilometres per hour, the most fuel efficient speed, when scheduling lines up right. Large railway companies are looking at the very expensive prospect of building more rail lines, either by doubling up track or by adding new routes. Mr. Spencer is correct about railbed quality. Broken or dis- torted rails are a major cause of derailments. Fortunately, there have been significant improvements in railbed design in the last few decades, such as concrete or composite ties, welded rails, and spring versus spiked-rail retention. The next leaps forward, now under development, are in sensing technology to look for deteriorating track and deteriorating truck assemblies (essentially wheels and suspension). These technologies are getting closer and closer to real time and becoming less expensive.
There are opportunities to improve the whole tank car design. I am a founding member of Crude Oil on Rail Enterprises (CORE), a Canadian association of some 20 private companies engaged in all aspects of the crude oil loading and shipping industry, from engineering to technology. We are concerned with the future of this business and want to ensure any pending regulations are based on sound and practical principles. Which is where good engineering comes in. For example, by adding a thermal insulation shell on the outside of the steel tank (and inside the outer jacket) with a high thermal rating, we can decrease the threat of collateral fire explo- sions in adjacent tank cars. This is an important discussion. It will influence the viability of getting crude oil out of this province and to the markets. More importantly, can we Professional Engineers make this a safer
industry for our public? JIM BENEDICT, P.ENG. Calgary
* * *
Mr. Spencer’s points do make sense from the actual conveying point of view. However, the design — and even a federally forced upgrade to current tank designs — focuses on postponing tank failure when things do go wrong.
For more than fifteen years, Oncore Services and ECO-Technica have been providing complete engineering and construction project services. We’ve always worked hand-in-hand to ensure designs make sense and construction runs smoothly — which is why we decided to come together as one team. Our multidisciplinary services remain the same, but our name has changed to reflect the truly integrated nature of our work. Meet ONEC. We (still) take your projects from start to finish, so you never have to worry.
3821–78 Avenue, Edmonton, AB T6B 3N8 T 780 440 0400 OnecGroup.com ENGINEER. CONSTRUCT. COMPLETE.
SPRING 2015 PEG | 47
Made with FlippingBook flipbook maker