Locomotive foot pounds of torque?

[PYROOGOBBO]

Heya just a noob question

so you can see some diesel cars with lets say about 800 lbft of torque for like a high end pick up. maybe for towing a caravan.

I see trains have like tractive effort and that but lets say i put a train on a perfectly straight bit of road , how much pounds feet of torque would a train have? i read up about train engines themselves producing about 5000-6000 ft-lb torque, but those engines are usually powering traction motors? so it gets confusing?

 

[twpsaesneg]

You are comparing like for like - the car engine output is generally flywheel horsepower / torque and so is the rated power of diesel engines in locomotives.

Then you have transmission losses, which will be mechanical transmission in a car (gearbox) and generally electrical transmission in a train (generator driving traction motors).

The 10x difference in pulling capacity isn't due to these transmission losses, it's more to do with the acceleration difference - your 500bhp pickup will be able to accelerate 10 tonnes (more like 7.5 really given maximum towing weights etc in the UK) up to 60mph in well under 30 seconds, whereas your 3000hp loco will take a lot longer to get up to the same speed. Better accelleration + More weight = More power needed and it is not a linear relationship.

 

[hwl]

Heya just a noob question

so you can see some diesel cars with lets say about 800 lbft of torque for like a high end pick up. maybe for towing a caravan.

I see trains have like tractive effort and that but lets say i put a train on a perfectly straight bit of road , how much pounds feet of torque would a train have? i read up about train engines themselves producing about 5000-6000 ft-lb torque, but those engines are usually powering traction motors? so it gets confusing?

The big US Locos will be about 350,000 ft-lb at very low speeds (total at the wheels)

 

[edwin_m]

Multiplying the tractive effort by the radius of the wheels ought to get you the total torque.