by Nasadowsk
<i>Uh, are you considering the new Tier II emissions regs?</i>
Yes. Prior to them, it was no contest at all - highway diesels were FAR cleaner. And highway diesels are about to get tightened up again by quite a bit. EGR, partical traps, catalysts, etc are all common on new highway diesels, and unheard of on rail diesels. It remains to be seen what happens when GE and GM are finally forced to adopt these features.
<i> And from what I've seen in the industry literature, locomotive energy efficiency is increased too.</i>
A few percent. Even GE and EMD's antique prime mover designs are actually quite efficient - about 40%, better than turbines. The world record is over 50%, but this was for a 3 or 4 story tall, 100 rpm unit - it spins so slow that there's lots of time to get energy out. The trouble is, overall, because the tyrains are so heavy, they're still not very efficient. IIRC, a two car IC3 gets better than 3mpg, which is far better than a P-40 pulling 2 Amfleets, or better than the CRC unit, which uses highway diesels anyway (which is why getting it past the EPA wasn't an issue - the engines already met a far stricter standard). Even a six car train would get 1mpg, which beats a conventional train by a lot, and with better performance to boot. because it's not lugging around a few hundred lbs of useless weight in the form of a locomotive.
Yes. Prior to them, it was no contest at all - highway diesels were FAR cleaner. And highway diesels are about to get tightened up again by quite a bit. EGR, partical traps, catalysts, etc are all common on new highway diesels, and unheard of on rail diesels. It remains to be seen what happens when GE and GM are finally forced to adopt these features.
<i> And from what I've seen in the industry literature, locomotive energy efficiency is increased too.</i>
A few percent. Even GE and EMD's antique prime mover designs are actually quite efficient - about 40%, better than turbines. The world record is over 50%, but this was for a 3 or 4 story tall, 100 rpm unit - it spins so slow that there's lots of time to get energy out. The trouble is, overall, because the tyrains are so heavy, they're still not very efficient. IIRC, a two car IC3 gets better than 3mpg, which is far better than a P-40 pulling 2 Amfleets, or better than the CRC unit, which uses highway diesels anyway (which is why getting it past the EPA wasn't an issue - the engines already met a far stricter standard). Even a six car train would get 1mpg, which beats a conventional train by a lot, and with better performance to boot. because it's not lugging around a few hundred lbs of useless weight in the form of a locomotive.