World's highest railway -- powered by GE

[Allen Hazen]

So much heat, so little light!
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As for the trucks on the Tibetan locomotives. To my eye, going by the photos I have seen on the WWWeb, they look very much like the trucks on the Australian NR-class locomotives. (The NR is a repackaged -- different carbody to reduce weight and fit closer clearances -- Dash-8/Dash-9 used on mainline freights over the Australian standard-gauge network.) I believe that the design principles are similar to those on the "Roller Blades" Hi-Ad trucks used on U.S. Dash-9 locomotives, but lightened in weight. I'd love to know more!!!
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Q1: are the trucks for the Tibetan locomotives made in Erie, or did GE subcontract this to somebody, and if so, who?
Q2: is it generally true that, if you want to reduce the weight on locomotive trucks, you go for a fabricated truck instead of a cast frame?

[pablo]

I spent some time last night looking for more information on the new locos for Tibet, since now my curiousity is up. I couldn't find much. Specs are curiously hard to come by, but being a Chinese entity...

Someone please correct me if I'm wrong...but arent Hi-Ads about as good as you can get minus radial steering, and other such technological gizmos? If the Tibetan line is as straight as it's rumored to be, radial steering wouldn't be necessary either. Since there aren't many 4 axles being built today (not counting Green Goats, etc., though I'd like to know what type of trucks those new locos being built for the LIRR look like) I'd imagine that new development might have ceased, but my understanding is that once the "crack" issue is resolved in Hi-Ads, they're quite good.

Anyone?

Dave Becker

[Allen Hazen]

I'm rather surprised at the limited market penetration Radial trucks have had, at least in the parts of the locomotive market the major North American suppliers deal with. As far as I know, GE has never even demonstrated a Radial truck with DC motors -- suggesting that even its experience of several hundred SD70MAC locomotives with radials didn't convince BN that curve resistance and track damage from conventional C trucks was worth getting rid of: otherwise they wouldn't have acquired their vast fleet of Dash-9 units with Hi-Ads! Nor has UP seemed to feel the need... despite operating the main lines of the WP and D&RGW, whose former owners seem to have stuck with 4-axle diesels for a long time in deference to their curves.

Mystery.

As for Hi-Ads... Well, even if they have struggled to match EMD's engines for reliability, GE is a first-rate engineering company with a mastery of the "fundamentals" of locomotive design, and they came up with the Hi-Ad design after comparing notes with European engineers (the design has Krupp influence) and testing one of the best earlier North American designs (the "Dofasco" truck used on MLW units). So it ought to be good! And, IF the truck on the Tibetan locomotives is the Australian variant, it is at least well-tested: a fleet of 120 NR-class locomotives has been in use for a decade+.

[pablo]

I thought something like that was at work with these trucks. I get to see Hi-Ads every day (or, any day I wish to) and i know they are valuable, if the cracks are prevented or otherwise absent. To see them still being produced today suggested that they have value and are no engineering shortcut.

Thanks for your insight.

Dave Becker

[es80ac]

I'm rather surprised at the limited market penetration Radial trucks have had, at least in the parts of the locomotive market the major North American suppliers deal with. As far as I know, GE has never even demonstrated a Radial truck with DC motors -- suggesting that even its experience of several hundred SD70MAC locomotives with radials didn't convince BN that curve resistance and track damage from conventional C trucks was worth getting rid of: otherwise they wouldn't have acquired their vast fleet of Dash-9 units with Hi-Ads! Nor has UP seemed to feel the need... despite operating the main lines of the WP and D&RGW, whose former owners seem to have stuck with 4-axle diesels for a long time in deference to their curves.

Mystery.

As for Hi-Ads... Well, even if they have struggled to match EMD's engines for reliability, GE is a first-rate engineering company with a mastery of the "fundamentals" of locomotive design, and they came up with the Hi-Ad design after comparing notes with European engineers (the design has Krupp influence) and testing one of the best earlier North American designs (the "Dofasco" truck used on MLW units). So it ought to be good! And, IF the truck on the Tibetan locomotives is the Australian variant, it is at least well-tested: a fleet of 120 NR-class locomotives has been in use for a decade+.

There are 2 things going against the GE "Steerable" trucks. 1 is that due to EMD's patent restrictions, GE's version had to be intentionally complicated. The second thing is the cost. Even with EMD's radial truck, which many claim is a master piece of simplicity, there is significant amount of extra cost associated that the railroad don't feel is justified at this point.

The US locomotive trucks (mainly the various versions of the floating bolsters in the GE c trucks and EMD HTC and Flexicoil) all seems rather primitive compare to European versions. Look at the Swiss/German locomotive trucks from the same period. The Hi Ad trucks is a step in the right direction. I just wish they would have put the Hi Ad trucks on the Tibetan locomotives, the Tibet line certain does have the axle load to support it.