The HO GP38-2 might be on a tad on the heavy side. Weight would scale with volume as a cube of the scale. A full size GP38-2 weighs about 250,000 lbs. That's would scale to only 6 ounces (16*250,000/87^3) in HO.
Ray Hamilton
Horsepower and pulling power (better known as tractive effort) are, at best, nodding relations. Two steam locomotives could each develop 2,000hp. The high-drivered but light weight 4-4-0 could go like the wind with a three car train. The low-drivered 2-8-0 might reach 35mph, but there would be fifty freight cars behind it.
So-called 'slugs' make use of the horsepower available but not used at low speed to provide more tractive effort for use in shoving a full-length train over the hump of a gravity yard. The horsepower of the prime mover is the same, but the tractive effort is doubled.
As for the mass of a model, and equivalent HP and TE, you have to divide the prototype number by the cube of the scale to get an answer. This is useful if you are tank testing ship hull designs, but I don't think it need concern us as model railroaders.
Chuck (Modeling Central Japan in September, 1964)
I suspect there is some, but little correlation. Most Big Boys will outpul moguls, however...
But more specifically, for example, I have a Genesis GP9, the prototype having 1750HP, and a LifeLike P2K E6, having two engines that total 2000HP. I suspect my HO E6 would outpull two GP9s, as the E6 has 50% more wheels per loco for traction, and it's more than 10% or so (the HP difference per loco) heavier (has a huge weight). And tractive effort is more related to torque and friction factor than horsepower per se (more acceleration related, IIRC).
And of course you get into pulling power (ala torque in an auto) versus accelleration ability (ala acceleration in a dragster which is HP related), gearing, max speed, etc.
I think you should stop drinking coffee before bedtime.
Paul
Modeling HO with a transition era UP bent
Yes, just go to sleep.
The only thing that scales is the physical volume that the object takes up. An HO scale GP38-2 doesn't weight a ton and a half, does it? That's 1/87th of the weight of a real one.
Hello All,
In one of my sleepless moments I was wondering if the horsepower rating of a prototypical locomotive actually translates to the pulling power of the same models on my pike?
For example: a GP 40 is rated at 3,000 hp, a GP 38-2 is rated at 2,000 hp; which, for the sake of argument, has one-third less pulling power.
Given that both the GP 40 and the GP 38-2 I own are from Bachmann, I was wondering...If they are assembled from the same components: prime-mover (D/C motor) and traction motors (dog-bone to worm gear to B-B trucks) how can they have differing pulling power as per the prototypicals?
Any thoughts???
Maybe I should just get a sleep-aid!?!
"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"