• Bolsterless power trucks (non-selfsteering)

  • General discussion about locomotives, rolling stock, and equipment
General discussion about locomotives, rolling stock, and equipment

Moderator: John_Perkowski

  by locomotive112
Sometime in the 1980's and 90's all the major the diesel locomotive builders started using "Bolsterless trucks" (ALCO/MLW/BDD was first, GM second, GE last) that had no center plate and no bolster. The trucks do have a large pin (Don't call it a center pin when talking to one of the builders engineers!) that does some centering, but ton these new trucks the spring rubber stacks do everything, they; hold the locomotive on the trucks, produce massive centering forces, and they can also change the amount of weight on either end of the trucks.

I can see how the bolsterless trucks would perform fine on a railroad that had no tight curves and also limited curvature (most std gauge RR's), and the trucks were only ever required to swing out a small amount, but visualizing the function of these modern trucks on a locomotive that had to negotiate a railroad that had a high number of very tight curves, I forsee issues.

With the old bolster & centerplate version you could adjuste the centering forces by removing a couple of the spring rubber stacks, or using weaker stacks. On the new bolsterless trucks the spring rubbers have to be there to hold the locomotive off of and above the trucks and therefore the spring rubber stacks are always going to be installed and are going to be strong & heavily sprung versions that are going to produce a high centering force that cannot be altered much.

So my question is; Does anyone have any knowledge of these bolsterless trucks being a problem (flange wear, rail wear, derailments. etc..) on a railroad that has tighter than typical curves and a great amount of curvature in general?

There are both self steering (up to 6-degrees) and regular non-flexible non-selfsteering trucks, these plain trucks (but bolsterless) are the versions I was asking about.
A specific example would be the DOFASCO trucks on the ALCO and MLW/BD locomotives. They offered bolsterless trucls since the ealry 1980's, on both export and domestric (Canada and USA) models that only use the spring rubber stacks to keep the trucks seperated from the locomtives frame.
  by kaitoku
Locomotive112, re. bolsterless bogies (trucks), I'm talking about emu's in Japan rather than locomotives (btw there are bolsterless bogie electric locos here too), but certain railways still specify bolster-equipped bogies when ordering new rolling stock (the majority of new rolling stock is bolsterless equipped). Apparently they believe the risk of derailment at low speeds on sharp curves is slightly higher with the bolsterless design. This arose from the Hibiya Subway Line derailment on 160m radius curve at Naka-Meguro in 2000, which resulted in 5 passenger fatalities. Quite a few Tokyo Metro rolling stock designs now utilize bolster bogies, despite their heavier weight.