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Originally Posted by milomilo
I haven't ever seen any convincing case for the effectiveness of the US rail safety strategy of building trains like tanks. What difference does it make if a European DMU hits a 2km long CP freight train or a 400m Deutsche Bahn freight train head on? The end result is going to be similar, there's no way you can engineer any train to safely withstand thousands of tonnes travelling at 100+km/h. In Europe they use the amazing strategy of not having an atrocious safety record and not having the trains crash in the first place, which seems to work much better.
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There is a significant difference. The mass of the "400m Deutsche Bahn freight train" will likely be within an order of magnitude of the DMU. As a result, you will see a significant reduction in speed of the freight train, meaning that all you have to worry about is surviving the rapid deceleration resulting from the crash. For this type of collision, crumple zones work well.
The mass of the "2km long CP freight train" will be significantly higher than the mass of any passenger train (likely more than 2 orders of magnitude (for those who don't know, an order of magnitude is a power of 10, 1 order of magnitude is 10 times, 2 orders of magnitude is 100 times, etc)). That type of collision is analogous to a bug on a windshield and the freight train will barely slow down. As a result, after the initial collision, the freight train is still moving with significant speed and it will push the passenger train out of the way. To survive that kind of collision, you need a ridged frame that will keep the passenger compartment intact until the freight train eventually comes to a stop. That makes the train significantly heavier.
The increased mass is a consequence of the design, not a desired effect. The use of lighter, high strength materials (like aluminum) can make the train lighter and still be just as safe, since the passenger train will always be significantly lighter than mainline freight trains.
Quote:
Originally Posted by milomilo
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I have seen similar arguments. The problem is they completely ignore the differences in types of freight trains that exist in North America compared to Europe.
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And the FRA did change the rules! So if you think the rules are good, the FRA says you are wrong.
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You have to understand that the change in rules didn't actually change anything. The new rules don't allow the use of European DMUs everywhere and anywhere, but instead put strict conditions on when and where they can be used. Before these new rules came into effect, it was still possible to use European DMUs, but the rail operator needed to apply for an exemption and since the FRA hadn't made it clear when and where an exemption would be granted, this was considered a risk. As a result, some rail operators went with conventional trains to avoid that risk. These new rules make it clear where the FRA will allow European DMUs and where it won't.
TC does allow European DMUs, you just need to apply for an exemption (like the City of Ottawa did for its Trillium Line). They could publish rules similar to the FRA's, but there hasn't been much interest in using European DMUs here in Canada, so it hasn't been worth the effort. If that changes, we may see a similar policy here.
The advantage of not having a preset policy is that safety is relative and there are many different factors that contribute. With an exception process, if you can provide a convincing argument that your operation will be safe, it will be approved even if it wouldn't have met the letter of the law of a set policy.
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