Tractive force of a loco
- Thread starter Mobi
- Start date
gregh
electronics, computers and scratchbuilding
As Rik said, you can use a scale. But you need to find one with a max reading of around 1kg. The largest tractive effort I have measured on my locos is 700 grams. (I know, it should be in Newtons, so multiply by 10 if you must)
I can't get any pics to upload, so you'll have to imagine it.
I realised that measuring the force with the motor powered an wheels slipping is the same a just pushing the unpowered loco along !
So I just use the scale to push the loco and there’s your answer!
If you only have a ‘larger’ scale that measures more than 1kg, another method is to take a piece of track, put the loco on it and raise one end till the loco slides down the grade. Measure the height and length of track where the loco just starts to slide, divide height by length and multiply this by the weight of the loco = tractive effort
I wrote an article about tractive effort and determining prototypical loads for my trains – see here:
http://www.gscalecentral.net/tm?m=108636&high=tractive
I can't get any pics to upload, so you'll have to imagine it.
I realised that measuring the force with the motor powered an wheels slipping is the same a just pushing the unpowered loco along !
So I just use the scale to push the loco and there’s your answer!
If you only have a ‘larger’ scale that measures more than 1kg, another method is to take a piece of track, put the loco on it and raise one end till the loco slides down the grade. Measure the height and length of track where the loco just starts to slide, divide height by length and multiply this by the weight of the loco = tractive effort
I wrote an article about tractive effort and determining prototypical loads for my trains – see here:
http://www.gscalecentral.net/tm?m=108636&high=tractive
ge_rik
British narrow gauge (esp. Southwold and W&LLR)
Brilliant Greg!gregh said:
I do like it when something seemingly complex can be explained in terms which I can readily comprehend. The link to the original article looks really interesting. I might have a go at calculating the real load limits for the locos on my line - I'm hoping my max of eight 4 wheel goods wagons will be about right (that's the maximum length I can fit in a passing loop). I'm sure I read a book about the Welshpool & Llanfair that the max length of their trains was 10 wagons (inc brake van) which had a max gradient of 1:33.
Rik
chris m01
Registered
I have two power ratings for my locos - sufficient and insufficient. Sufficient means sufficient for expected duties on my line so the locos that pull my USAT California Zephyr train have to have a lot more adhesion than a switcher type loco which only needs to be able to pull six mineral wagons.
So long as a loco has sufficient power for required duties then it doesn't matter how much more it could pull. If a loco doesn't have sufficient power for required duties then lead will be applied. If this fails then the errant loco will be dispatched via ebay. No time for slackers on my line.
Any testing outdoors is likely to be full of inaccuracies. We saw last weekend at whatlep's (thanks for a great afternoon Peter) that a loco's ability to climb pootank pass changes during the course even of an afternoon. Although the afternoon was dry throughout sometimes the ICE would conquer the pass with no worries and sometimes it failed miserably (to the delight of the assembled crowd).
So long as a loco has sufficient power for required duties then it doesn't matter how much more it could pull. If a loco doesn't have sufficient power for required duties then lead will be applied. If this fails then the errant loco will be dispatched via ebay. No time for slackers on my line.
Any testing outdoors is likely to be full of inaccuracies. We saw last weekend at whatlep's (thanks for a great afternoon Peter) that a loco's ability to climb pootank pass changes during the course even of an afternoon. Although the afternoon was dry throughout sometimes the ICE would conquer the pass with no worries and sometimes it failed miserably (to the delight of the assembled crowd).
3Valve
Railways; Air cooled VW's; Soul Music
yb281 said:1) stick loco on track
2) attach rolling stock
3) operate loco. If it pulls the train, all is well. If it doesn't, take stock off until it does.
Shimples.
Take to Peter's Stick, on the track at the bottom of Pootank pass. Stick ten hoppers on the back. If it pulls em up. Tractive force good. If it doesn't tractive force poor.
Take some cash with you, you may need some lead.
Also refer to "audible GSC meter".3Valve said:yb281 said:1) stick loco on track
2) attach rolling stock
3) operate loco. If it pulls the train, all is well. If it doesn't, take stock off until it does.
Shimples.
Take to Peter's Stick, on the track at the bottom of Pootank pass. Stick ten hoppers on the back. If it pulls em up. Tractive force good. If it doesn't tractive force poor.
Take some cash with you, you may need some lead.
If all so gathered go "Oooooooooo" = tractive power good.
If all so gathered do the dying fly and break into hysterical laughter = tractive power bad.
3Valve
Railways; Air cooled VW's; Soul Music
yb281 said:Also refer to "audible GSC meter".3Valve said:yb281 said:1) stick loco on track
2) attach rolling stock
3) operate loco. If it pulls the train, all is well. If it doesn't, take stock off until it does.
Shimples.
Take to Peter's Stick, on the track at the bottom of Pootank pass. Stick ten hoppers on the back. If it pulls em up. Tractive force good. If it doesn't tractive force poor.
Take some cash with you, you may need some lead.
If all so gathered go "Oooooooooo" = tractive power good.
If all so gathered do the dying fly and break into hysterical laughter = tractive power bad.
I've only ever heard the latter
Just as well there's no video evidence then mate.3Valve said:yb281 said:Also refer to "audible GSC meter".3Valve said:yb281 said:1) stick loco on track
2) attach rolling stock
3) operate loco. If it pulls the train, all is well. If it doesn't, take stock off until it does.
Shimples.
Take to Peter's Stick, on the track at the bottom of Pootank pass. Stick ten hoppers on the back. If it pulls em up. Tractive force good. If it doesn't tractive force poor.
Take some cash with you, you may need some lead.
If all so gathered go "Oooooooooo" = tractive power good.
If all so gathered do the dying fly and break into hysterical laughter = tractive power bad.
I've only ever heard the latter
spike
It's me
Three bricks in my Dash 9 the fuel tank was full of lead.
One more car made it slip on my 2.5% grades.......
http://www.youtube.com/watch?v=zUyDTAH1Rtk
One more car made it slip on my 2.5% grades.......
http://www.youtube.com/watch?v=zUyDTAH1Rtk
ge_rik
British narrow gauge (esp. Southwold and W&LLR)
Does anyone know what happened on the W&LLR if the amount of traffic for the daily goods train required more than 10 wagons? Did they just send some of it by the following day's train or did they run an extra train on the day? I'm sure I've read somewhere that they split heavy goods trains to get up Golfa Bank - presumably taking half up and then returning for the other half. Weren't there some accidents caused on some railways by splitting trains which left unbraked, poorly scotched portions to run off down the line?
I doubt they would muster a second loco to double-head a weighty freight train on my light railway - I'm assuming they would split it in some way.
On the W&LLR they had no choice over which type of loco they could muster - at least on the Southwold they had three different types of loco they could choose for a particular train (assuming they were all in working condition). I'm thinking it would add an interesting extra dimension to operations to have to decide which loco to allocate to which train to match the anticipated load.
Rik
I doubt they would muster a second loco to double-head a weighty freight train on my light railway - I'm assuming they would split it in some way.
On the W&LLR they had no choice over which type of loco they could muster - at least on the Southwold they had three different types of loco they could choose for a particular train (assuming they were all in working condition). I'm thinking it would add an interesting extra dimension to operations to have to decide which loco to allocate to which train to match the anticipated load.
Rik
CoggesRailway
Registered
OK this is how you really test G scale tractive effort http://www.youtube.com/watch?v=m17v... don't think it work now, the load has grown!
ge_rik
British narrow gauge (esp. Southwold and W&LLR)
At risk of answering my own question, I've consulted a couple of my books about the W&LLR and it looks as if they increased the number of goods trains if the traffic demanded it. On some market days for example, it seems they ran up to five fully loaded goods trains in a day.
Now that's got me thinking...........
Rik
Now that's got me thinking...........
Rik
playmofire
Registered
trammayo said:
I thought of that one, Mick, and tried to find the book in which I'd read about it to confirm date and place but couldn't. If I remember rightly, the driver had expressed concerns about the length of the train but had been over-ruled by the local manager and told to run the train as it was, The driver was right and the train had to be split. The accident led to new regulations on braking systems I believe.