Europe seems to have adopted hydraulics which don't seem to have caught on in the United States. What is the advantage of a hydraulic and why were they not accepted here?
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The biggest problem with hydraulics is maintenance. The diameter of each wheel on the truck must be kept within a millimeter of the others or the difference in torque will break the drive shafts.
Electric drives (with the exception of EMD's original AC motor units) allow a greater variation in the diameter of the wheels before there are any problems.
Stuart
Does that mean our railroads just don't want to pay for maintenance of a better system?
Why would they think it is worth paying for?
European railroads also don't haul the tonnage that U.S. railroads do. How many photo's have you seen of European trains with 4-5 locomotives on the point?
D&RGW (3) and SP (24, including the ex-DR&GW units) tried diesel hydraulics and they suffered with reliability problems.
Rusty
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Originally Posted by GVDobler:
Does that mean our railroads just don't want to pay for maintenance of a better system?
Why do you think that it is a "better system"? The hydraulic drive has proven that it is NOT capable of withstanding the extremely heavy haul loads on North American Railroads. That is why AC Traction has become so popular, especially in Australia.
Why would they think it is worth paying for?
European railroads are more interested in high speed, and not slow speed heavy haul unit trains such as what we have in this country.
There are also other reasons for diesel-electric propulsion. One axle can slip while the others do not. With a hydraulic drive and shaft connected axles, all axles on a truck slip at the same time.
European trains don't use our couplers and train tonnage is not nearly as heavy. Maybe they don't have the adhesion challenges that North American freight trains must deal with.
Hot Water
i didn't phrase it right. But the answers clear it up.
