Gradients when laying track
- Thread starter ASG
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CoggesRailway
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yep I have found weighting locos helps alot. they are generally too light relative to rolling stock i reckon. like most things in life it is probably about moderation!
beavercreek
Travel, Art, Theatre, Music, Photography, Trains
Westcott said:
Yeah okay okay It just happens I do have a Bachmann K27 and an Accucraft one as well. But that weight is spread over 4 axles which does help. But as Stainzmaster has said, he has used lots of weight in his locos with no detriment so it must be fine.
So as I said I do stand corrected.
korm kormsen
Registered
well, the grades don't let me sleep.
on my new layout i use 13 meters (42') to gain 70 cm (2' 4") of height.
that would be 5.4% (after my mileage)
that was the steepest grade on which my small locos (with additional weight) could draw up trains of 14 aixles.
any steeper trial produced nothing but slipping locos.
so, now i am told, that one can use 1 in 5 grades (for me = 20% grade)
that means i should need only 3.5 meters (11' 4") for that difference in height.
i really would like to know, how i could save that much space.
but my locos don't even move themselves up this grade. (let alone a string of cars)
to visualize about what we are talking, i took a 150cm (5') piece of rail and a 30cm (1') piece.
the resulting one in five (20%) grade looks like this:
on my new layout i use 13 meters (42') to gain 70 cm (2' 4") of height.
that would be 5.4% (after my mileage)
that was the steepest grade on which my small locos (with additional weight) could draw up trains of 14 aixles.
any steeper trial produced nothing but slipping locos.
so, now i am told, that one can use 1 in 5 grades (for me = 20% grade)
that means i should need only 3.5 meters (11' 4") for that difference in height.
i really would like to know, how i could save that much space.
but my locos don't even move themselves up this grade. (let alone a string of cars)
to visualize about what we are talking, i took a 150cm (5') piece of rail and a 30cm (1') piece.
the resulting one in five (20%) grade looks like this:
spike
It's me
Just to add a bit to what Rod pointed out.
How you would size a loco for a particular job.
Here are the main factors that govern tractive effort.
You can scale these weights to models, if you so wish, by dividing by the cube of the scale.
The tractive effort required to move a train consists of numerous factors, but for most applications only four need to be considered.
First, a force of 2 to 5 pounds per ton of train weight is required to move on straight level track.
At very slow yard speeds only 2 to 3 pounds is needed while increasing to about 5 pounds at higher speeds.
This force is required to overcome bearing friction, rail deflection, minor flange contact, etc.
The second factor to consider is track curvature.
Cars in a curve require a good deal of tractive effort because the wheels are mounted on solid axles. Thus the wheels must slip and slide through the curve because of the difference in radius of the inside and outside rails. Wheel flange contact adds additional friction.
For the cars in the curve, the tractive effort required is 0.8 pounds per ton per degree of curvature,
The percent of grade is perhaps the most important factor governing tractive effort.
For every ton of train weight in a grade, 20 pounds of tractive effort is needed for each 1% of slope. (One percent of a ton or 2000 pounds equals 20 pounds.) A 1% grade is defined as a vertical increase of one foot for each 100 feet of horizontal distance. A 1% grade is considered steep; a 2% grade is unusually steep.
The final factor and one frequently overlooked is the tractive effort required for acceleration of the train.
It takes about 10 pounds per ton to accelerate to a speed of 6 miles per hour in one minute or 12 miles per hour in two minutes, a reasonable rate for a heavy train.
Increasing this tractive effort increases the acceleration rate proportionately.
How you would size a loco for a particular job.
Here are the main factors that govern tractive effort.
You can scale these weights to models, if you so wish, by dividing by the cube of the scale.
The tractive effort required to move a train consists of numerous factors, but for most applications only four need to be considered.
First, a force of 2 to 5 pounds per ton of train weight is required to move on straight level track.
At very slow yard speeds only 2 to 3 pounds is needed while increasing to about 5 pounds at higher speeds.
This force is required to overcome bearing friction, rail deflection, minor flange contact, etc.
The second factor to consider is track curvature.
Cars in a curve require a good deal of tractive effort because the wheels are mounted on solid axles. Thus the wheels must slip and slide through the curve because of the difference in radius of the inside and outside rails. Wheel flange contact adds additional friction.
For the cars in the curve, the tractive effort required is 0.8 pounds per ton per degree of curvature,
The percent of grade is perhaps the most important factor governing tractive effort.
For every ton of train weight in a grade, 20 pounds of tractive effort is needed for each 1% of slope. (One percent of a ton or 2000 pounds equals 20 pounds.) A 1% grade is defined as a vertical increase of one foot for each 100 feet of horizontal distance. A 1% grade is considered steep; a 2% grade is unusually steep.
The final factor and one frequently overlooked is the tractive effort required for acceleration of the train.
It takes about 10 pounds per ton to accelerate to a speed of 6 miles per hour in one minute or 12 miles per hour in two minutes, a reasonable rate for a heavy train.
Increasing this tractive effort increases the acceleration rate proportionately.
beavercreek
Travel, Art, Theatre, Music, Photography, Trains
Wow Mike...I am amazed in admiration.:-
Between yourself and Korm's investigations, this is like watching an episode of Horizon on TV or The Discovery Channel. I think that you have given the definitive thrust to force to friction info.
Spectacular in the extreme.
I will now go and acquire some roll lead (local church roof looks inviting...ONLY KIDDING) and place it into my locos as well as using the traction tyres and my woes will be cured. I will still triple head ('cos it looks good) but I will get more out of my single locos.
Korm, those who have visited my garden layout can affirm the steepness of the grades even if you obviously have disbelief. I feel honored that you have investigated so thoroughly to disproove the situation but unfortunately the situation exists. As I said it is 15% on the steepest part going up and 20% on the steepest going down. These gradients eventually meet at the summit (Arbour Summit). It is difficult taking a picture to show you as the way the track is behind rocks and is partly obscured by bushes. :wave:
Between yourself and Korm's investigations, this is like watching an episode of Horizon on TV or The Discovery Channel. I think that you have given the definitive thrust to force to friction info.
Spectacular in the extreme.
I will now go and acquire some roll lead (local church roof looks inviting...ONLY KIDDING) and place it into my locos as well as using the traction tyres and my woes will be cured. I will still triple head ('cos it looks good) but I will get more out of my single locos.
Korm, those who have visited my garden layout can affirm the steepness of the grades even if you obviously have disbelief. I feel honored that you have investigated so thoroughly to disproove the situation but unfortunately the situation exists. As I said it is 15% on the steepest part going up and 20% on the steepest going down. These gradients eventually meet at the summit (Arbour Summit). It is difficult taking a picture to show you as the way the track is behind rocks and is partly obscured by bushes. :wave:
once a customer told me (while i tried to fizzle in a decoder in his HO-V200 from Märklin) that he found out why his loco pulls only sone cars up an incline, while the prototypical loco can pull strings of them.
While the "big" loco weighs about 80 tons, calculated down in size the model should have a weight of 80/87 tons what makes about 920 kg.
Oh dear, i had to fight hard not to shout out loudly laughing my ass off.
On the other hand, even spike-mikes rules are just something to lead on.
There are so many factors going inside the facts, that it is impossible to make deatiled and matching rules.
Just let me give the example of the loaded ton:
a ton of trainweight runs easier depending on a loaded train than on an empty one...the more the wagons are loaded, the easier ever single ton goes. But just up to a peek of "easy rolling" after what the bearings and axles are overloaded and beginning to hold back the easy rolling.....and so on!!!!
So, i tried to find some tables, but didnt find. For that i calculated on the base of the sometimes complicated calculation-system of the US-railroads.
Therefore i found out:
on an incline of about 4-5 % (20-25 cm lenght per 1cm height) a Bachmann-Connie should take between 180- and 200 prototypical tons of trainweight.
for a average weight on axle of max. 10 tons in narrow gauge, that means that the train is complete with 4 loaded hoppers and a Caboose.
With empty flatcars, it can take a string of 20 cars or so.....
On this thoughts i built up my plans for the layout. And therefore i "tuned" up my Connies to pull that weight. Not more!
greetings
Frank
While the "big" loco weighs about 80 tons, calculated down in size the model should have a weight of 80/87 tons what makes about 920 kg.
Oh dear, i had to fight hard not to shout out loudly laughing my ass off.
On the other hand, even spike-mikes rules are just something to lead on.
There are so many factors going inside the facts, that it is impossible to make deatiled and matching rules.
Just let me give the example of the loaded ton:
a ton of trainweight runs easier depending on a loaded train than on an empty one...the more the wagons are loaded, the easier ever single ton goes. But just up to a peek of "easy rolling" after what the bearings and axles are overloaded and beginning to hold back the easy rolling.....and so on!!!!
So, i tried to find some tables, but didnt find. For that i calculated on the base of the sometimes complicated calculation-system of the US-railroads.
Therefore i found out:
on an incline of about 4-5 % (20-25 cm lenght per 1cm height) a Bachmann-Connie should take between 180- and 200 prototypical tons of trainweight.
for a average weight on axle of max. 10 tons in narrow gauge, that means that the train is complete with 4 loaded hoppers and a Caboose.
With empty flatcars, it can take a string of 20 cars or so.....
On this thoughts i built up my plans for the layout. And therefore i "tuned" up my Connies to pull that weight. Not more!
greetings
Frank
Neil Robinson
Registered
FWIW when adding weight I try and even out the weight distribution. IMHO the loco should neither be front or rear heavy but balance in the center of the driven wheelbase. Very few if any models of steam locos take much of the loco's load on any front or rear trucks, so I tend to remove them when checking the balance, assuming that they just support their own weight when on the track.
Provided a loco is symmetrical, side to side balance should not be an issue, with the likes of a Shay though it may be worth checking.
Provided a loco is symmetrical, side to side balance should not be an issue, with the likes of a Shay though it may be worth checking.
trammayo
Interested in vintage commercial vehicle, trams, t
So, against all the aforegoing technical information - whats it all mean in simple terms? I like to be simple. If you divide the old (UK?) way of expressing a gradient as, say, 1 in 15 then divide that 15 into 100 will give the modern (almost universal?) expression as 6.6% - am I correct? Just as 1 in 20 will give 5%.
Mick
Mick
beavercreek
Travel, Art, Theatre, Music, Photography, Trains
Just to affirm all that has been mentioned in the thread.
My steep grades can be surmounted by using multiple loco lash-ups, auxiliary motorised rolling stock and traction tyres (all of which I do at present) and can be enhanced further with the judicious use of lead weight.
BUT I have a couple of Bachmann Annies and I have read and discussed that they can, due to the use of not the highest quality plastic, be prone to stripping their cogs even on slight inclines with a good string behind them. Has anybody really loaded them up with lead and had a good reliable running experience when using inclines (normal sized inclines that is - not like mine) and a goodish string of cars?
My steep grades can be surmounted by using multiple loco lash-ups, auxiliary motorised rolling stock and traction tyres (all of which I do at present) and can be enhanced further with the judicious use of lead weight.
BUT I have a couple of Bachmann Annies and I have read and discussed that they can, due to the use of not the highest quality plastic, be prone to stripping their cogs even on slight inclines with a good string behind them. Has anybody really loaded them up with lead and had a good reliable running experience when using inclines (normal sized inclines that is - not like mine) and a goodish string of cars?
Correct Mick!
Exept the thing that there are old or new methods to name a gradient.
In many countries the RR prefered the 1: X method and do it up till now.
Thats because of the general technical "norm". Many things in metal engineering are measured in "1:X", and not in degrees.
The % method is just "more common".
Even though most people dont know how to use this correct, too.
But:
Yes, u got it right!
15 goes 6.66 times in 100, so such an incline is 1: 15 or 6,66% or 66,6‰ or 3,81 degrees.
Frank
Exept the thing that there are old or new methods to name a gradient.
In many countries the RR prefered the 1: X method and do it up till now.
Thats because of the general technical "norm". Many things in metal engineering are measured in "1:X", and not in degrees.
The % method is just "more common".
Even though most people dont know how to use this correct, too.
But:
Yes, u got it right!
15 goes 6.66 times in 100, so such an incline is 1: 15 or 6,66% or 66,6‰ or 3,81 degrees.
Frank
spike
It's me
trammayo said:
Correct
Just to show it's faily easy to work out grades as degrees and % if you have a half decent calculator.
If you know the % the degrees =arctan %/100
arctan is just the inverse of tangent.....(just use your calculator with inverse on and use the tan button)
Example 5% grade =arctan 5/100
=arctan 0.05
=2.8degrees.
you can work this backwards as well
degrees of slope=tan degrees x 100
Example 2.8degrees slope=tan2.8 x 100
=0.0489 x 100
=4.89%
trammayo
Interested in vintage commercial vehicle, trams, t
Thanks Frank.
Its all to do with the Metric system I suppose. But even in your part of the world, the Whitworth screw thread is still used for overhead line fittings for trams and trolleybuses. Even France, the pound (as a measure of weight) is not dead (neither is it here in Ireland) but your'e not supposed to use it in the UK.
Its hard when you are brought up with feet and inches or miles per hour to adjust! For a number of years we had distances in kilometers but speeds in miles per hour. Now its all kilometers!
Mick
Its all to do with the Metric system I suppose. But even in your part of the world, the Whitworth screw thread is still used for overhead line fittings for trams and trolleybuses. Even France, the pound (as a measure of weight) is not dead (neither is it here in Ireland) but your'e not supposed to use it in the UK.
Its hard when you are brought up with feet and inches or miles per hour to adjust! For a number of years we had distances in kilometers but speeds in miles per hour. Now its all kilometers!
Mick
spike
It's me
korm kormsen said:
Hi Korm.
I have just done a quick test like yours.
No pics but set up a 1:5 grade with a length of Aristo stainless track.
Did'nt have time to test every loco but these I did.
Dash 9 fully weighted...........managed to move up but ended sliding back down.
GP9 weight as is......moved easily upgrade no slipping.
F3A weight as is......moved up but not as easily as the GP9
Bachmann Annie......could'nt hold itself on the grade at all just slid back down
beavercreek
Travel, Art, Theatre, Music, Photography, Trains
spike said:Dash 9 fully weighted...........managed to move up but ended sliding back down.
GP9 weight as is......moved easily upgrade no slipping.
F3A weight as is......moved up but not as easily as the GP9
Bachmann Annie......could'nt hold itself on the grade at all just slid back down
Hi Mike
I use mainly F3 A&Bs, GP9s and GP30s and they all perform well (as long as they are lashed up) other locos need lashups and also sometimes the addition of auxiliary motorised rolling stock (stock car with two USAT motor blocks instead of normal bogies). This enables them to climb my grades (as said before, at the steepest 15-20% 1:7- 1:5.5). My Accucraft K27 can get up with the use of two auxiliaries to pull short string of ball-bearing bogied cars. LGB Uintah mallet can get up on its own using traction tyres but can't pull anything unless lashed up and/or using auxiliary. Annies...ah the Annies..well they need an auxiliary to pull one coach.
Finally the shays, climaxes do well with short strings and the surprise when I was testing my layout at the very beginning was that An NW-2 could do it and pull a couple of cars as well. Most of my diesel stuff is USAT (for the traction tyres but also as they do a couple more types that were actually used on the Rio Grande system) but I do have some Aristo and they do have problems without help as they have no traction tyres.
The Uintah mallet is going to be renamed to the Beaver Creek Railroad that is why it is in the collection!
beavercreek said:
Thank goodness you're only kidding. We've had nearly £5000 of damage done this year by lead thieves (which is now the limit on claims set by our insurers), and that's just the flashing and collateral damage, three times - it gets much, much worse if you are one of those churches where the roof itself is lead rather than slate.
Richard (a churchwarden)
trammayo
Interested in vintage commercial vehicle, trams, t
spike said:
Hi Mike - I can't even remember my Clines or anticlines or anything to do with Pythagorus or his chums. I used to work everything out in my head but can't defrag the hard drive now!
I know what you mean though, its just getting my head round it! Simple things for me these days.
Mick
korm kormsen
Registered
Spike,
thank you for the data.
that was unweighted to 400grms additional weight.
with 600 grms additional lead it went on strike.
i did not look yet, but i suppose the tooth-fairy was busy.
but that is typical for me.
now, after i finished good part of my long incline, i get information, that i might have done with less space...
i know somebody, who will make lots of tests during next month.
thank you for the data.
well, my starterpack big hauler did slip on my 6% grade, when trying to draw up just its own tender.beavercreek said:
that was unweighted to 400grms additional weight.
with 600 grms additional lead it went on strike.
i did not look yet, but i suppose the tooth-fairy was busy.
but that is typical for me.
now, after i finished good part of my long incline, i get information, that i might have done with less space...
i know somebody, who will make lots of tests during next month.
spike
It's me
trammayo said:
Hi Mick know what you mean.
Trig was'nt my hottest subject, can remember a few things from way back when
I think if we all stick to the height over length ratio.......ie 1:50 etc......we know where we stand.
When we get into degrees of slope it can get confusing.....still its good to get the brain working