Apparently there is going to be a common purchase of diesel locomotives for the California and Midwest services. What is the proposed maximum axle load going to be? In Europe I doubt that it would be more than 22 metric tons or 24.2 US tons because of rail wear at the maximum speeds involved (110 mph). I would hope similar thinking would apply here rather than the overweight locomotives Amtrak and most commuter railroads currently have. If they are going to be lighter then they might be useful for the Talgos.
AMTK's PRII spec. (which will govern the design of these locos) does not specify a maximum vehicle weight or axle loading.
What is specified is the need for a 'weight optimization program'...and the need for the locos to meet certain requirements as to generation of dynamic forces on the railhead.
A weight limitation of 24 tons per axle would result in a light (by North American standards) locomotive. Consider that a standard North American 4-axle locomotive tended to weigh in at 120-125 tons, hardly overweight.
I doubt that the axle load of the E7 or E8 locomotives in the 1940s was that much higher than 24 - 25 tons with their A1A + A1A trucks and a single unit could handle 5 cars on the CNW Chicago - Milwaukee line at speeds up to 100 mph. A locomotive this much lighter would be easier on the track and curves and MIGHT allow the Talgo equipment even faster speeds on curves. For the day trips involved, high acceleration is a major need and i hope someone realized that is more important than the very highest speed.
As to American locomotives not being overweight from a European point of view, the axle loadings mentioned are for the 100 to 125 mph speeds and they require lower weight for tilting equipment.
The weight on axle was around 50,000 lbs for EMD units. Current government regulations for passenger locomotives that share trackage with freight trains requires buff strength(collision posts/anticlimber) and a crew 'refuge' are in the vcab area. A typical 4 axle diesel locomotive meets all of the mandated safety regulations will weigh at least 250,000 lbs. The operator can file for an exemption.
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
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