Western Railroad Discussion > Retrofitting radial (HTCR) trucks on older locomotives

A railfan friend of mine suggested to me that it would be a great idea to install EMD HTCR radial trucks underneath a SD-9 or a SD40-2 in order to make these locomotives more suitable on a shortline branchline.

Obiviously anything can be done with enough time and money, but would such an operation actually be feasible to improve locomotive performance on tight radius curves?

Of course, cost is a main factor in my question...

Thanks!

Save your money. If the curves are that tight use a GP.

No, seriously. I'm curious too, and I've often wondered the same thing. We run SD9's on a three percent plus grade with 16 degree curves in places, and it's hell on wheels. (Litterally...) Always have at least one unit down for wheels, either lathing or replacement.

Geeps aren't sufficient because of the gradient. I'd have to use six or seven to do the work of the SD's. Higher HP units also aren't sufficient because of the speeds (10mph, which doesn't let a higher HP unit develop enough tractive effort)

Are the HTCR trucks a longer wheelbase?

Jody

Don't scoff, EMD had a Dash 3 rebuild prototype SD 40 fitted with HTCR trucks and other computer control goodies. As you can see it didn't get much interest. An BTW the HTCR is better in cures than a GP. The real problem is the total weight of the locomotive on branch structures.
Paul

pmpete wrote:

> Don't scoff, EMD had a Dash 3 rebuild prototype SD 40 fitted
> with HTCR trucks and other computer control goodies. As you
> can see it didn't get much interest. An BTW the HTCR is better
> in cures than a GP. The real problem is the total weight of
> the locomotive on branch structures.

also, they have EMD 3, one of the original SD60
demos, that also has HTCR trucks retrofitted.

Del wrote:

> Save your money. If the curves are that tight use a GP.

Here's the example:

Portland & Western Mac Hauler, McMinnville to Beaverton. Over Rex Hill, SP used to run between 4-6 SD-9s over the hill.

Willamette & Pacific later used GP39-2s (and typically only three or four of them) on their train. Less track wear, but also less tractive effort. Trains frequently were doubled over the hill.

Today, Portland & Western is assigning four to six GP39-2s and GP40-2s, along with slugs on this train.

A SD locomotive would provide more tractive effort and spread the weight over six, not four axles.

Jody's right on the money, the POTB is even a more extreme example of where this idea could be implemented.

Don't need to go to a 3-axle truck. EMD developed a prototype radial B-truck about the same time as the HTCR. I suspect that the added cost and complexity weren't seen as worth the added expense. I remember seeing a photo of it in x2200 South. More recently, the Alaska RR has modified the blomberg trucks on some of its GP40-2s so that they function in much the same manner as a radial truck.

pmpete wrote:

> Don't scoff, EMD had a Dash 3 rebuild prototype SD 40 fitted
> with HTCR trucks and other computer control goodies. As you
> can see it didn't get much interest. >

Nope, EMD does not have a DASH 3 rebuild with HTCR's retrofitted. EMD #2000 was rebuilt from a straight SD40 and as part of the rebuild it was given HTC trucks in place of the original flexicoil trucks. Due to the added length of the HTC trucks, a 3000 gallon fuel tank had to be used in place of the original 4000 gallon tank. This is just one of the major reasons that the various SD40-2 rebuilds, ect. rebuilt from pre DASH 2 units have not had the flexicoil trucks replaced, not to mention the added expense.
You could retrofit the HTCR trucks in place of the HTC truck, as EMD did with its SD60 test unit #3, but it would likely be very costly to do so. To retrofit an older unit (pre DASH 2) equiped with Flexicoil trucks to HTCR's would likely be very expensive, maybe not even possible.
FWIW, EMD is introducing a new, non radial truck called the HTC-S on 2 of the new EMD SD70ACe demo uits, I think GM 70 and 72. They look the same as the HTCR, but don't have all of the added linkage which allow the radial trucks to operate the way they do.

Bryan Jones

According to the mechanical man at the PS&P rairoad EMD has a retro fit kit to make standard 3 axle trucks more flexible to cause less rail wear but Rail America will not pay for it ( they will pay more in the end when they have to replace the rail ). The Mech mann said the 2 SD45T-2's they have are wearing the rail down at an alarming rate on Stimson hill between Shelton,WA and Elma,WA. Stimson is a 2.8% grade with some fairly sharp curves because of that hill they have 2 SP speed lettered SD45T-2's that still look great. Works for me I just hope they do not put them aside because of the rail waer problem. I will admit it did make for an easy chase back before the 6 axles because they always had to double the hill.

Scott

How about GP's mated to 4 axle slugs (cut down scrap units)? Assuming similar weight on all axles you will have 33% greater low speed TF per mother + slug as you have 8 axles instead of 6. At low speeds it's all about weight on drivers not horsepower.

At the same gear ratio you will also have a lower minimum continuous speed so speed can drop lower without risk of burning out traction motors. It's possible you could get away with running the trains with 2 of these sets instead of the 3 SD's with a considerable savings in maintenance cost. Or you can run 3 sets and up the tonnage. Either way the wheel and rail wear will be greatly reduced.

Steve