Allison trans?

[rsb502]

If anyone doubts Allison transmissions ability to pull a load and maintain slow speeds without overheating here's a pic of a Western Star with a 475hp Cat and a 4500 series Allison that just dumped three carloads of ballast.

[Reuhlz]

I just purchased an Allison 3000 series to put in an old Mack someday. I know I would be losing two sticks, but there are trade-offs (like double overdrive). Thanks for the pic!

[umodelnut]

I bet the U model'd pull that in first gear.

[BOB DINGSDALE]

as long as you have tracktion and weight you can go till you stall torque converter.I pulled 200+tons of logs plus weight of truck and two trailers up 10 to 13% grade with 525 KTA and 6061 allison in 1st and 13.298 rears.no problem.

[rsb502]

Yeah, that was only about 600,000 lbs behind him, of course once you get it rolling its not that bad, stopping is something else entirely. The way we empty old hoppers full of ballast is complete B.S., we have ballast cars but they wont let the local gangs use them so we have to put a rr tie on the track in front of the back wheels of the car we are unloading, use a come along on each side hooked to the unloading door and slowly open it leaving it open just enough to spread the ballast, then as the truck pulls the cars they spread the rock and the tie that is being pushed by the rear wheels screeds the rock level with the top of the rail. After the rock is down and the truck and cars are back in the siding the ballast regulator and tamper come to tamp it and grade the ballast.

[Gmerrill0516]

If memory serves, the force to pull one ton of weight on rail, on level track is 10 pounds. You have to overcome very little rolling friction on tracks. That is what makes the railroad so efficient. You still need to pull it up hill and keep it from rolling down too fast but it's not like pulling on rubber. Alison transmissions are good stuff just the same. Mack ran them in the 60's in the real big trucks with 100,000+ ratings. Lots of persistent grunt to make stuff move.

[rsb502]

The force needed once moving is less, getting it moving is the key, then you have to add the dragging a railroad tie in front of the car wheels pushing a pile of rock to the equation. That truck basically serves as a locomotive, and ballast regulator all in one when were unloading rock. Ive seen them pull 10 loaded cars before, not a big deal once moving but they don't like to get rolling on any kind of grade, and you have to consider the 200,000-286,000# weight limits on each car, so figure 1000 tons for ten cars to be on the low end.

[theakerstwo]

A torque converter is a torque multiplier.

[Reuhlz]

If memory serves, the force to pull one ton of weight on rail, on level track is 10 pounds. You have to overcome very little rolling friction on tracks. That is what makes the railroad so efficient. You still need to pull it up hill and keep it from rolling down too fast but it's not like pulling on rubber. Alison transmissions are good stuff just the same. Mack ran them in the 60's in the real big trucks with 100,000+ ratings. Lots of persistent grunt to make stuff move.

Force = mass x acceleration. Looks like there is a LOT of mass. Therefore, depending on how fast you want it to move (accelerate) will be your force input. 10 pounds per 1 ton doesn't seem right in my head, but i am not a railroad guy.

Drew

[MACKS]

A torque converter is a torque multiplier.

Yup,it just a matter of whats gonna break first,rear,drive shaft or you can just rip the engine and tranny from the mounts,thats how much torque those tyranny's put out..

[rsb502]

gmerrill is right the railroad claim to fame is low rolling resistance, I don't know what it takes to move the weight but most railcar wheels are 33 or 36" diameter and have a contact patch on the rail about the size of a dime. The flange isn't there to keep it on the rail thru curves either (well kinda) the rail wheels are actually tapered not flat and the taper of the tread centers the wheelset between the rails, if everything is right the flange should never touch the rail, thus reducing friction.

[storkmack]

gmerrill is right the railroad claim to fame is low rolling resistance, I don't know what it takes to move the weight but most railcar wheels are 33 or 36" diameter and have a contact patch on the rail about the size of a dime. The flange isn't there to keep it on the rail thru curves either (well kinda) the rail wheels are actually tapered not flat and the taper of the tread centers the wheelset between the rails, if everything is right the flange should never touch the rail, thus reducing friction.

Just learned something. Very interesting.

[rsb502]

heres a drawing from a patent for a certain type of wheel profile, there are multiple radii that have to be turned in sequence to get it right, its a nightmare to try to read.