Gradients

[40009]

I have just started to plan a new layout (my first for nearly 25 years). What I am unsure about is the maximum gradient that I can get away with. I will be operating Hornby, Bachmann and Heljan deisel locomotives. The maximum trains will be 8 coaches and 20 bogie wagons.

 

Anyone out there got any idea?

 

Thanks in advance.

 

Rob

[Kenton]

Generally a lot less steep than you may think.

Less if there are any curves.

 

Some locos are better than others at traction and others are near useless. Most locos do not get better (assuming they have been run-in) they get worse over time. Also remember that the track gets dirty and that can affect the power/traction.

 

I think for OO it is a general rule that 1:50 is about doable but 1:100 better

 

The real answer is to rig up a test track and try it out with your own locos and stock.

[40009]

Thanks very much. Now I need to think again.

[Ajax]

Thanks very much. Now I need to think again.

 

With the modern can motor and all (most) wheel drive 1:40 gradients with 8 to 10 coaches isn't a problem even with moderate curves.

 

However with the older panckae motors it's a different matter!

[Kenton]

Take a look at Eastwood Town Gordon S's multi-level layout that has many gradients and has a good series of photos (though more in the currently RMWeb3 inaccessible archive).

If you are thinking multi-level the other big catch is that you need far more clearance between levels - access to get in there to manhandle derailments etc.

[BrushVeteran]

The modern diesels from Bachmann, Heljan & Hornby are quite heavy and have good haulage capacity. I use my layout which is 33ft x 10ft to test certain locomotives and have two 1 in 40 gradients in both directions on the mainlines (staight track). My test trains are a 9 coach Bachmann set of Mk 1's and 50 iron ore tipplers also from Bachmann. The best performer I have seems to be the Hornby class 31 which has managed to start 120 tipplers on the gradient and will crawl around all day set on 8 on my Lenz LH100. On the other end of the scale the Bachmann class 20 and the Heljan Clayton just about manage the 50 tipplers up the gradient so they are probably matched quite well to the prototype in terms of haulage capacity. If I really want to be cruel I insert a Roco track cleaning wagon between the loco and the train and that does make them grunt a bit. Unfortunately the same cannot be said about the superbly detailed steam loco's from both Bachmann and Hornby. Regretfully I had to get rid of 68 Eastern Region steam locomotives (all post 1999 loco drive) that wouldn't get up the gradients with even half these loads. Very dissapointing......and expensive! I do however have a the latest Hornby unrebuilt BoB 'Sir Winston Churchill' which is packed with lead and can manage 7 Mk.1's, so we are getting there.

Getting back to the original question 1 in 40 represents approx. a 3inch rise in 12ft which is enough to get one line over the top of the other. It does depend on how much space you have (I have a large loft) but I wouldn't recommend anything steeper as going down can be as interesting as going up. All my loco's are chipped with back emf decoders so the speed is constant.

[OFFTHE RAILS]

Come on Brushveteran !

A 1 in 40 gradient = 3" in 120" which at 12" to the foot is 10 feet not 12 ...

[gordon s]

.....or of course it could be 12' after all, in which case the gradient is 1:48 not 1:40. This is nearer to the figures that Kenton gave.

 

Thanks for the mention Kenton and I totally agree with you. You may get away with 1:50 with heavy diesels, but RTR steam locos will struggle with 8 coaches over much less that 1:100 particularly if you bring curves into the equation.

[Kenton]

One thing I certainly didn't include in my estimates was the use of DCC as opposed to DC.

 

I guess it is certain that DCC driven locos will achieve better traction. If only because the constant 12v applied to the track will eliminate one of the variables. But also the more finite control (the back-emf decoders - used by BrushVeteran for example) are bound to be an improvement over any bog standard DC knob twiddling. Steam loco models in particular seem prone to wheel slip and once traction is lost then often very difficult to regain.

 

When testing the loco must be able to start and continue from a standstill - no prototypical run at it

 

Of course with DCC you always have the option of introducing a prototypical banker

[DonB]

Way back when, probably in the 1960s , I recall (IIRC) the American Railroad people (NMRA) issuing guidelines for gradients, includng ideas for gradually easing into and out of the slope. Of course these ideas are not easily adopted by Space-strapped Europeans!

Does anyone have a reference or link to this historical gem, or is it only available to NMRA members via a Handbook or data sheet? Gradients are a frequently recurring topic.

[BrushVeteran]

Come on Brushveteran !

A 1 in 40 gradient = 3" in 120" which at 12" to the foot is 10 feet not 12 ...

 

 

.....or of course it could be 12' after all, in which case the gradient is 1:48 not 1:40. This is nearer to the figures that Kenton gave.

 

Thanks for the mention Kenton and I totally agree with you. You may get away with 1:50 with heavy diesels, but RTR steam locos will struggle with 8 coaches over much less that 1:100 particularly if you bring curves into the equation.

 

 

Way back when, probably in the 1960s , I recall (IIRC) the American Railroad people (NMRA) issuing guidelines for gradients, includng ideas for gradually easing into and out of the slope. Of course these ideas are not easily adopted by Space-strapped Europeans!

Does anyone have a reference or link to this historical gem, or is it only available to NMRA members via a Handbook or data sheet? Gradients are a frequently recurring topic.

As Don B rightly points out, the gradient has to start and finish, so as I said, I recon my gradient is still approx. 1 in 40 allowing for a foot either end for the transition of the angle. My comment wasn't meant to be a mathematical formula rather an example of what the gradient is on my layout over a rise of 3inches over 12 ft. I hope I haven't misled anybody but I did go and check upstairs.

[BrushVeteran]

Come on Brushveteran !

A 1 in 40 gradient = 3" in 120" which at 12" to the foot is 10 feet not 12 ...

 

 

.....or of course it could be 12' after all, in which case the gradient is 1:48 not 1:40. This is nearer to the figures that Kenton gave.

 

Thanks for the mention Kenton and I totally agree with you. You may get away with 1:50 with heavy diesels, but RTR steam locos will struggle with 8 coaches over much less that 1:100 particularly if you bring curves into the equation.

 

 

Way back when, probably in the 1960s , I recall (IIRC) the American Railroad people (NMRA) issuing guidelines for gradients, includng ideas for gradually easing into and out of the slope. Of course these ideas are not easily adopted by Space-strapped Europeans!

Does anyone have a reference or link to this historical gem, or is it only available to NMRA members via a Handbook or data sheet? Gradients are a frequently recurring topic.

As Don B rightly points out, the gradient has to start and finish, so as I said, I recon my gradient is still approx. 1 in 40 allowing for a foot either end for the transition of the angle. My comment wasn't meant to be a mathematical formula rather an example of what the gradient is on my layout over a rise of 3inches over 12 ft. I hope I haven't misled anybody but I did go and check upstairs.

[BrushVeteran]

Come on Brushveteran !

A 1 in 40 gradient = 3" in 120" which at 12" to the foot is 10 feet not 12 ...

 

 

.....or of course it could be 12' after all, in which case the gradient is 1:48 not 1:40. This is nearer to the figures that Kenton gave.

 

Thanks for the mention Kenton and I totally agree with you. You may get away with 1:50 with heavy diesels, but RTR steam locos will struggle with 8 coaches over much less that 1:100 particularly if you bring curves into the equation.

 

 

Way back when, probably in the 1960s , I recall (IIRC) the American Railroad people (NMRA) issuing guidelines for gradients, includng ideas for gradually easing into and out of the slope. Of course these ideas are not easily adopted by Space-strapped Europeans!

Does anyone have a reference or link to this historical gem, or is it only available to NMRA members via a Handbook or data sheet? Gradients are a frequently recurring topic.

As Don B rightly points out, the gradient has to start and finish, so as I said, I recon my gradient is still approx. 1 in 40 allowing for a foot either end for the transition of the angle. My comment wasn't meant to be a mathematical formula rather an example of what the gradient is on my layout over a rise of 3inches over 12 ft. I hope I haven't misled anybody but I did go and check upstairs.

[Dr.Glum]

My layout has a straight length of 1 in 42, which doesn't actually go anywhere yet (it'll be another 2 to 3 years I reckon), but will be the 'down' of a down-and-up reverse loop under the layout. The 'up' will be 1 in 90 on straights and about 1 in 130 on curves. There are few rail joints, and those few are very close fitting. There are no visible dips or humps in the length.

 

I went up last night to run some tests on the 1 in 42. I didn't bother testing the Deltic or a Class 37; they are so heavy. I know the Deltic will pull more than any of those shown below, and certainly more than I can fit on the slope (which is 9 carriages).

 

Test results with Backmann Mk1s (~160grams each) and half carriage represented by Hornby Shark brake van (~80grams), in no particular order:

 

Hornby 'A1A' 9 carriages medium speed, possibly starting to slip (hard to tell)

Hornby 'Brit' 7 carriages medium-fast, slight slip

Bachmann 'Jinty' 4 carriages slow, slight slip

Bachmann 'Fairburn' 5.5 carriages medium-fast

Bachmann '9F' 7.5 carriages medium

 

If you introduce curves, the maximum possible train load goes way down, as mentioned by the other posters. I did some tests a few years ago that included curves (not a quick exercise to arrange) and concluded that with minimum 30inch curves of 90 degrees (quarter turn) the gradient on the curves would have to be at least half the straight gradient. Most of the data I've kept relates to older split-chassis Bachmann locos which cannot pull up gradient so well as current locos from Hornby or Bachmann, usually due to wobbly wheels. One useful fact did remain: an unaltered Lima HST set with 8 carriages could go quite easily at reasonable speed up 1 in 85.

Good modelling, Tony

[Sam Moss]

Every christmas at our model club we always have a haulage contest. This year a Hornby Duble 2 rail Duchess romped away with the prize. It managed to haul without slipping, 39 coaches cosisting of Bachmann, lima, Hornby etc up a 1:39 gradient round a reasonable sharp curve. We didn't try it with any more and were were having trouble fitting the consist within sections. Second place went to my Clan Line managing 28 with slipping. On the diesel side a class 60 and a vitrains 37 tied. The 37 did surprisingly well and it was one without traction tyres. The only thing that stop us using it was the dodgy coupligns that swing out derailing the first bogie.

[Miss Prism]

Some good data there, Tony, and it seems to confirm a 'rule of thumb' sometimes quoted in USA model practice that a sharp curve, on a gradient or otherwise, requires up to (depending on the actual radius of course) approx 50% more traction compared to straight track.

[nswgr1855]

There is no difference between DCC and DC when it comes to traction. It's purely a function of locomotive weight on driving wheels, driving wheel rail friction and the total drag from friction and weight of the train and drag of non traction wheels.

 

Terry Flynn

 

 

http://angelfire.com/clone/rail/index.html

 

HO wagon weight and locomotive tractive effort estimates

 

DC control circuit diagrams

 

HO scale track and wheel standards

 

Any scale track standard and wheel spread sheet

 

One thing I certainly didn't include in my estimates was the use of DCC as opposed to DC.

 

I guess it is certain that DCC driven locos will achieve better traction. If only because the constant 12v applied to the track will eliminate one of the variables. But also the more finite control (the back-emf decoders - used by BrushVeteran for example) are bound to be an improvement over any bog standard DC knob twiddling. Steam loco models in particular seem prone to wheel slip and once traction is lost then often very difficult to regain.

 

When testing the loco must be able to start and continue from a standstill - no prototypical run at it

 

Of course with DCC you always have the option of introducing a prototypical banker

[Gwiwer]

There's a lot of good information there already so I'll just add a few points from my own experience. I am able to run prototype length trains (up to 16 coaches double-headed) because I have a long run but that doesn't give me scope for prototypical gradients. There are some rather steep stretches though they are short and the longer gradients are rather more gentle.

 

Everyone has their own unique situation with the size, shape, theme and gauge of the layout all coming into play. So there are no hard and fast guidelines only rules of thumb. The first of these is that any gradient must be as easy as can possibly be made. The next is to keep the track straight where possible. As well it doesn't matter what you do there is always going to be something which objects to some part of your layout.

 

Trains need to overcome gravity and inertia to move and they need to do this using only a 12V motor and a few tiny points of contact from the driving wheels. The more you couple onto the hook the greater the force which has to be overcome. Sooner or later any given loco will not be able to overcome those forces and will slip or stall no matter what you do.

 

Curved track creates a huge amount of drag which must be added into the equation. If the curve is also on a gradient you massively increase the amount of force required to get a train around the layout. I (intentionally) created a steep start from one of my stations with trains trailing back around an S-bend (reverse-curve) through the platform. It's the hardest spot from which to re-start a train without causing a slip. But provided the train doesn't exceed the maximum load for the loco it can be done.

 

Here's a clip of some very skillful driving from the "crew" of a Hornby "West Country". From a standing start on the 1:36 and around the dreaded reverse-curves they get the train going without a hint of slip. The gradient is fairly obvious and when you count you will find there are SEVENTEEN bogies on the hook!

 

The couplers you choose to use will also have an effect on the ability of a loco to haul a train uphill. Much though I hate the huge T/L couplers of older Hornby and Lima they are well fixed to (or moulded as part of) the stock itself. Push-fit couplers such as Bachmann, Heljan and most recent Hornby use can pull out with a heavy load on the drawbar or if a train snatches on starting. The chances of that occurring are higher on an uphill start or if your train slips them regains its feet with a jerk. I don't use Kadees and can't offer advice on how they perform.

 

There are other tricks which can be employed to ease the gradient. One of the best is to have a "splitting gradient" where instead of one line trying to get up and over another on the level one track rises while the other falls. You can achieve the required vertical separation in half the horizontal distance by this means which can be used to shorten a steep climb or to employ all the space available and create gentler gradients. The effect as employed on my layout is demonstrated by this short clip of freewheeling wagons.

 

Don't forget that what goes up must come down. it's not just getting a train up the hill which matters. Running down a very steep bank can cause the couplers to compress, over-ride and create a derailment. Or the train accelerates wildly and rips into the corner at a scale speed a jet aircraft would be happy with. Or usually some blend of those two. Again the heavier the train the more the tendency for the tail to wag the dog - or to push the loco! After all we might have lighting, sound and DCC control but we don't yet have continuous air brakes on our rolling stock. We in effect rely on the old Class 9 unfiitted freight type with only the loco providing any brake force. If you don't believe that try shutting off the power as a train rolls smartly downhill and check how far it is pushed by the train after the power reaches "off". That can sometimes be several centimetres.

 

Trial and error is not perhaps the ideal way to discover whether your prized loco and best coach / wagon rake will do what you require of it but it can often be the best. No-one can predict exactly how your model will perform in your circumstances. Bachmann and Heljan items generally do better than Hornby, and recent Hornby does better than anything older / fitted with a pancake motor or branded Lima. But that is no guarantee of happy and trouble-free days at the control panel. There is no easy way to ensure those.

[Michael Delamar]

debating on building a permenant layout in the loft which was similar to our old 1980s layout which had an underground fiddle yard, however we used to have steel track, magnetic triang locos etc. this will be 00 finescale with handbuilt points and modern rtr steam and diesels dcc.

 

we dont have much space, 12ft x 10ft, boards will be approx 3ft all round,

 

the theme will be the steep lines down to docks around liverpool such as bootle junction where one line comes up from underneath another joins it then drops back down again,

 

1960s london midland region period so black 5s. austerities, 8fs etc, mainly freight and mainly rtr stock, train length will be determined by fiddle yard sidings length, some passenger

 

from my back of a beer mat drawing, I think it will be too steep for modern rtr steam? diesels should be ok.

 

im wondering what others who are a lot more cleverer and experienced think.

 

 

prototype inspiration.... http://en.wikipedia...._under_LCSR.JPG

[Silver Sidelines]

Hello

 

I use rakes of seven coaches, Bachmann Mk1s, and Hornby Staniers and Hawksworth. Gradients are around 1:56 and the minimum clearance is 2 1/2 inches (Three inches if you include the thickness of the layout board). Whilst Bachmann and Heljan diesels just trundle along, most Bachmann and Hornby Steam need additional lead shot. My layout has lots of curves and I would say that some steam models seem to perform better on curves where they can get some purchase from the curving track (minimum radius 36 inch / Peco Medium Radius). I note the comments above regards Bachmann split chassis types and would disagree, my Bachmann Scots and Patriots with additional lead shot out shine the latest Hornby City and Princess. The following are old links and are due to be updated now that ballasting is almost complete but they should provide some food for thought:

http://youtu.be/wG21nBMRkpY

 

Regards Ray

[Kris]

I think that it will be too steep Michael. Looking roughly you are going to end up with a gradient of between 1:20 & 1:25.

[Michael Delamar]

cheers Kris

 

i think if I swap it round and have the gradients the other side it should be better, and spread it out as much as possible until they dive under the other line, also keeping the curves as gentle as possible, only downside is its further to reach if something goes wrong, but i want the double crossover as it also gives us the opportunity to leave 4 trains running if we want to, this layout isnt just for me to enjoy

 

[Kris]

Doing that makes far more sense. You should be able to get 1:40 - 1:50 gradient.

[Michael Delamar]

i thought itd be shallower than that Kris, trying to get it down to 1,100, ignore the 5ft, if the stretch of incline is around 10 ft say even if it has a curve on it?

[Kris]

To get 1:100 you'd need a 25ft length of track to raise 3"