Pulling power of a loco, how to tell?

[JS84Z]

Hi all

I know that for a loco to have high pulling power, it needs to be heavy to avoid wheel slip. Manufacturers never give specifics on this so is there actually a way to know the pulling power of a loco or is the only way to find out is to play by the ear when you acquire a new loco?

[atom3624]

Weight is one thing.

Number of driven wheels - one or both bogies on larger diesels / electrics is another.

Traction tyres - not everyone's 'cup of tea' but they work is another.

In many cases weight can be 'adjusted' - there's generally room for more, but more is not necessarily 'the answer' - you can add too much, and in the wrong places.

Type of motor / condition is very important as well.

Al.

[Jimbo1707820979]

On YouTube young Sam has sometimes used a kind of "traction effort" meter to check pulling power. Does anyone know what the gadget is ? Something with no relation to model trains come to mind. Like a postal scale with a hook ?

[96RAF]

You can use digital kitchen scales by way of a simple bell crank to transfer the loco ‘buffer’ push to downwards on the scales.

[LTSR_NSE]

The measuring devices Sam uses are called Newton Meters or Force Gauges.

[96RAF]

Newton meter, which is an instrument of measurement, as opposed to Newton-metres which is a value of torque.

[37lover]

Jimbo,

A search on Ebay of "newton meter" will show several of different "capacities" at quite low prices. I will have to watch Sam's video to establish typical forces in order that a meter offering a suitable capacity can be selected.

[37lover]

I've just tried to edit my earlier post but nothing doing. I've watched one of Sam's videos where he pulls himself using 32 locos; I think he said 10N with 32 so on average that is 0.31N per loco in which case the 1N scale should be okay. A word of warning though; if the loco is pulling against restraint and not able to move then that is the "stall current" situation and you don't want to be doing that for very long!

[96RAF]

For reference I used to tighten up some big bolts to 800 Nm which equated to around 660 LbsFt of torque. For equivalent scale this was a mighty tug on a five foot torque wrench.

So for this exercise convert Newtons to pounds force and compare with pulling a bag of sugar.