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| Re: official Anouncement about MBTA HSP-46ac (973587) | |||
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Re: official Anouncement about MBTA HSP-46ac |
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Posted by WillD on Tue Aug 31 23:44:50 2010, in response to Re: official Anouncement about MBTA HSP-46ac, posted by Olog-hai on Tue Aug 31 22:36:22 2010. Why not new ones, especially ones that can be just as quickly adapted for commuter service? Won't be so cheap to rebuild old Geeps in the future.That remains to be seen. It is possible we'll see a line of new-build two axle road switchers, but that's extremely unlikely. There are *so* many more 2000-3000hp two axle switchers out there which lived lives easier than they were built for that it's unlikely we'll need new two axle switchers for at least 15 years. The RailPower, MPI, and other rebuilt locomotives are being constructed for lifespans of 15 to 20 years, which they'll likely exceed given the lower horsepower and less stress being put on the frame than their original prime movers created. But even when those locomotives do appear they won't exactly be high performance units, they'll be low horsepower road switchers just like the rebuilt units being churned out by MPI, NRE, RailPower, and so on. The days of the four axle fast freight locomotive died with the radial truck six axle units. They're easier on themselves and the rails, more stable up to about 65mph, and they allow railroads to purchase one basic unit for both hot intermodal, merchant, and drag freight. But like the SDP70F and E60CP years ago, it's debatable as to how these radial trucks with their non-rigid frames will hold up at higher speeds (of course the early Amtrak Co-Cos had rigid trucks). This all means any passenger locomotive with a speed upward of 70mph is going to remain an extremely niche product unless we greatly expand our commuter and state-level rail systems. Those were shadows of their former selves indeed. And little wonder. The railroads bought all those C430s, GP40s, U30Bs, GP50s, B36-7s, GP60s, and Dash 8-40Bs with visions of them leading faster intermodal trains dashing between major yards while reducing axle counts and thus maintenance budgets for those axles by a third. What they wound up with were units that sat in yards and frequently lacked the tractive effort to adequately supplement, let alone supplant six axle units on even the lightest of fast freights. In yard duty the four axle design meant they were insufficient for humping duties, but might be used to trim cars in the bowl. They were frequently consigned to branch line switching duties and when they ventured out onto the mainline, it was frequently in the company of six axle units within the locomotive consist. There are a few notable exceptions, such as BN's use of the LMX B39-8s in helper service over the Cascades, but by and large the four axle road units were never utilized as fully as their six axle counterparts. As such it really only makes sense to use four axle units in roles for which six axle units just make no sense, and those roles are now shrinking. As radial truck equipped SD70s and Dash-9s begin to be phased out of frontline service by the incoming SD70s and GEvo units it is likely they'll even replace the GP40s and so on in light duty branch line switching. Removing some ballast from the current coal haulers would likely reduce their axle loading to be equal or less than a four axle, 3000hp unit, and with radial trucks they don't have the minimum radius concerns of the old rigid three axle truck units. It's possible there will be a problem with operating articulated trucks on some of the really awful branch line and industrial track around the country. The only real salvation for the four axle units will be where they can really make a significant savings relative to a six axle unit. That means putting less strain on the motors with lower horsepower, and consuming significantly less fuel while producing a lot less emissions than their six axle counterparts. That is exactly the market most of the rebuilt four axle road switchers are positioning themselves for. That is precisely the market you'll see EMD or GE work toward if they ever produce a new-build four axle unit. I'd be surprised to see any non-passenger four axle unit, new build or rebuilt, with more than 2500hp under the hood built in the next 20 years. |
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