Helix or long ramp?

[33212]

Hello,

after some opinions and advice. I’m planning a new layout and will need to bring the trains up approx 2 feet in height, maybe a little more, from pre-existing storage sidings to the scenic part. I have the room for a helix, or as an alternative, I could run a ramp up between the two levels, maybe 60 feet in overall length, wrapped round the room. The question is, which performs better? Would a heavy train going down the ramp lose control? Anyone tried this?

thank you in advance.

[gordon s]

A 60’ run to rise a minimum if 2’ is only a 1:30 gradient. Far to steep if you are considering steam locos, where even 1:50 would be hard. Diesel loco’s fare much better, but in view of your comment re heavy trains, you should be aiming for 1:50. All of the problems will be going up the gradient........and as soon as you add curves you increase the problems.

 

There’s lot’s of info on helices here.......

 

 

Edited January 10, 2021 by gordon s

[HLT 0109]

You will need a very wide helix to do better than a 1:50 incline.  £rd radius curves need a 4'wide helix (approx) and in one circuit the track would be less than 13'long; in that distance (for 00 gauge) you would need to rise (say) 3"; ie 3:156.  If installing a double track, the inner circle would be steeper.

 

You could of course add operational interest by double heading the trains up the helix but then you woould probably need a place to stop to uncouple at the top.  I have a steep incline (insanely steep) on my loft layout and need three steam locos to haul 20 loaded wagine to the top round two, 90 degree curves using Hornby 3rd radius .  The track rises some 15" in about 25'.

 

Harold.

[Andymsa]

Hi,

 

I think we need a bit more detail of the types of trains and there lengths, is the ramp one way or will it be two way traffic. 

[faulcon1]

I think it all depends on what you want to achieve. If the helix is to be covered in as there's nothing more unrealistic than watching a British train negotiating a huge spiral, then you won't be able to watch the train ascend or descend the two levels. However an incline or ramp allows you to watch your train climbing the gradient and if you use DCC Concept's power base then even steam outline locos can climb steep gradients with ease, provided that your steam locos have a plastic plate that covers the axles for you need to screw the tiny magnets in place. Diesels have a lot more weight in them than steam locos and even steep gradients are no real problem for them. But it all depends on how long you want your trains to be and even with an incline you may want to employ banking locos like on the Lickey Incline where any train over three coaches had a banking loco or four on the rear. It also depends on what control your using because if you're using DCC and your worried about locos racing down a gradient, well that doesn't happen with DCC due to the back EMF in decoders which keeps the train at a constant speed. So if you set the loco to speed step 20 then it won't exceed that going down the grade no matter how many wagons are behind it.

But the choice is yours of course. 

[Andymsa]

4 hours ago, faulcon1 said:

I think it all depends on what you want to achieve. If the helix is to be covered in as there's nothing more unrealistic than watching a British train negotiating a huge spiral, then you won't be able to watch the train ascend or descend the two levels. However an incline or ramp allows you to watch your train climbing the gradient and if you use DCC Concept's power base then even steam outline locos can climb steep gradients with ease, provided that your steam locos have a plastic plate that covers the axles for you need to screw the tiny magnets in place. Diesels have a lot more weight in them than steam locos and even steep gradients are no real problem for them. But it all depends on how long you want your trains to be and even with an incline you may want to employ banking locos like on the Lickey Incline where any train over three coaches had a banking loco or four on the rear. It also depends on what control your using because if you're using DCC and your worried about locos racing down a gradient, well that doesn't happen with DCC due to the back EMF in decoders which keeps the train at a constant speed. So if you set the loco to speed step 20 then it won't exceed that going down the grade no matter how many wagons are behind it.

But the choice is yours of course. 

 

I have to disagree a bit with the constant speed downhill with bemf. I have a push pull train that shows up with a kind of yo yo effect going down hill because bemf is trying to compensate the weight of the train , so it speeds up then slows down and speeds up ect ect. Even going up hill a constant speed on a level track is much faster than going up the hill so as more of the train gets onto the helix it starts to slow down until such point a balance is achieved.

[The Johnster]

Roundaswings and bouts.  A spiral has a lower limit to the size of the curve radius, and this has to be taken from the inside radius of a double or quadruple track setup.  Curves on a gradient intoduce a corkscrew effect where the inside rail is steeper than the outside one, not to mention being a shorter top to bottom distance, and as railway locos do not have car-like differentials and most RTR ones have a rigid chassis, a loco specified for, say, a number 3 radius curve by it's producer might have problems on a number 4 curve on a gradient, especially a spiral, and this is before the haulage ability of the loco is taken into account.  So, on any curved gradient but especially on a spiral, it is advantageous to keep the radius of the curve as large as possible, which is of course directly contrary to the reason for employing a spiral in the first place, saving space!  This is one of the reasons that diesel/bogie locos manage better than steam; as well as the greater number of powered wheels and more advantageous configuration of ballast weight distribuiotn, and the more powerful motors that can be hidding in the body, the rigid wheelbases are shorter and  the bogie mounting allows play that will assit the loco to keep all it's wheels squarely on the track.

 

As to haulage, don't forget that a two foot rise in 60' of run is not quite 1 in 30, it's less than that because of the transition curves that you have to allow in the vertical plane to enable your stock to make a smooth transition from level to gradient at the top and bottom; the real gradient is more likely to be 1 in 28 or even less.  If you measure the gradient from it's bottom point to the top at one in 30, it will be steeper than that in the central  section, and 1 in 30 will be the average, not the steepest and it is the steepest point of the gradient that is going to cause stalls or slips, which will be worse if the steepest part is on a curve, especially a tight curve.. 

 

There are things you can do to ease the situation.  Obviously, any unwanted drag in the train is going to have an enhanced effect, so coaches with pickups for lighting, any that do not run smoothly, any with dicey back to backs, or bogie pivots that are not completely free moving will induce drag and your locos will do better if you can eliminate them.  Long wheelbase 4 wheelers will drag at the flanges on tighter curves, and be careful of buffer lock on the descents.  Bankers or pilot locos are perfectly acceptable on a 1 in 30 gradient; they would be needed in real life!   In the case of multiple unit trains, or modern fixed rake trains with power cars at each end, this is already provided for you, and diesel or electric outline locos can be given double power bogies.  You will be less able to get away with such cheating with steam.  Traction tyres might help, but they will ruin your slow running and spread crud all over your layout, so will cause as many problems as they solve. Pemanemt bar couplings must be able to move laterally and vertically or they will transfer stress points, which equate to drag, to the bogie pivots and possibly the wheels, and if the loco is near it's limit, not much is needed to to induce slipping or stalling.  If a slip starts, ease the power back until the diriving wheels grip again; you'll lose speed and vital momentum but you might be able to recover traction.  Increasing the power will just make the slip worse and you will lose any partial traction the loco might still have.  It's like driving a car on sheet ice; softly softly catchee monkey.

 

Give your locos the best possible chance by keeping the track, wheel treads and backs, and the pickups, as clean as you can; an interruption, even a nanosecond's, of current to the motor is the last thing you want at any time but especially when the loco is fighting for traction and momentum.  Slips are caused when the motor is delivering more power than the wheel tread footprint (miniscule anyway in 4mm) on the track cannot contain the motor's power, and are commonly started by a loco losing power momentarily and then trying to pick up again when it is restored, and causes no real problems except perhaps increased wear on bearings.  Stalls, caused by the motor having insufficient power to handle the load and keep moving, are more serious as the motor will quickly overheat; shut off power completely immedieately if this happens (especially if it's a coreless motor).

 

Never used it so can't recommend, but it might be worth your looking at DCC Concept's 'Powerbase' system, a magnet that affixes to the bottom of your locos and a magentic strip that you lay directly beneath the track to improve haulage, with the additional benefit that the magnetic attraction helps the loco to 'sit' on the rails, improving pickup.  I would think that a gradient of 1 in 30 or a helix that can rise 2 feet even in the maximum number of spirals possible (I know there's only one spiral, you know what I mean) to ease the gradient, which is limited by headroom, whatever the nominal gradient is, would benefit from this.

Edited January 11, 2021 by The Johnster

[Dagworth]

Can your long ramp go around the room twice and climb a foot on each circuit?

 

Andi

[DCB]

On 10/01/2021 at 20:06, 33212 said:

Hello,

after some opinions and advice. I’m planning a new layout and will need to bring the trains up approx 2 feet in height, maybe a little more, from pre-existing storage sidings to the scenic part. I have the room for a helix, or as an alternative, I could run a ramp up between the two levels, maybe 60 feet in overall length, wrapped round the room. The question is, which performs better? Would a heavy train going down the ramp lose control? Anyone tried this?

thank you in advance.

Maybe you should accept the concept is flawed  I have a 1 in 100 gradient and a 1 in 36 ish you can get a reasonable OO RTR steam outline  train up a 100 at a reasonable speed.  Or get the same train up a 1 in 30 double headed rather slower.   That means for ordinary trains to run at ordinary speed. to climb 2ft  needs 200 feet ( nearly 3 scale miles) plus the length of stations which need to be flatter than 1 in100 in model form as current RTR doesn't have brakes to run    That takes a long time for a train to cover( 3mins for an express maybe 9 minutes or more for a mineral) and is pretty much impractical.   In addition coming down the 1 in 36 many of my trains need half wave power, as Feedback or even full wave DC makes the locos surge and derail the stock as it bunches,  I reckon a 2ft elevation change needs  a 12 foot long Nellyvator or what ever its called.

Edited January 11, 2021 by DavidCBroad

[F-UnitMad]

On 10/01/2021 at 20:06, 33212 said:

I’m planning a new layout and will need to bring the trains up approx 2 feet in height, maybe a little more, from pre-existing storage sidings to the scenic part.

No one so far seems to have asked - WHY do the trains need to climb so high above the storage sidings??

If it was to climb over another scenic level, as per American basement empires, I'd understand it, but why is such an amount of headroom needed over storage sidings?

[JZ]

On my last layout, I had a climb of about 3½" on a 40' run and a return to bottom of about 14' = 1 in 48. Longest passenger trains required two locos and goods needed banking, but as it was Somerset & Dorset, it was all very prototypical. And it had a minimum radius of 36"

[Trog]

On 11/01/2021 at 18:16, The Johnster said:

.......and as railway locos do not have car-like differentials....... 

 

I think you will find that is one of the things the wheel coning is there for.

 

 

 

Things to consider for gradients are that steel rail gives better grip, and on curved gradients try and make down hill the inside track on the curve. Myself I had a 3rd and 4th radius helix with a gradient of 1 in 37, which gave little trouble, to reasonable length trains.

[Nova Scotian]

On 11/01/2021 at 16:23, F-UnitMad said:

No one so far seems to have asked - WHY do the trains need to climb so high above the storage sidings??

If it was to climb over another scenic level, as per American basement empires, I'd understand it, but why is such an amount of headroom needed over storage sidings?

This was my first thought. Any drop in the height required will ease the incline significantly. Same applies to any height that can be gained, transition inclines etc, within the rest of the layout. And any tricks to increase the horizontal distance of the incline will help (not as much as reducing the vertical distance though). That is, unless that trick involves curves, which increase friction and make it harder to climb the incline.

[33212]

On 10/01/2021 at 23:26, Andymsa said:

Hi,

 

I think we need a bit more detail of the types of trains and there lengths, is the ramp one way or will it be two way traffic. 

Hi - all diesel era types, 80’s with loco hauled trains 8 mk1/2 etc and various EMU formations up to 12 cars, freight into equivalent of 8/10/12 cars in length.

[33212]

On 11/01/2021 at 18:25, Dagworth said:

Can your long ramp go around the room twice and climb a foot on each circuit?

 

Andi

Could do, could hide it

[33212]

Because there are two existing fiddle yards at about 18” height from the loft floor, and the old layout was in front at the same height. This was good when started and in use 15 years ago, but you have to reach over everything to get to it. Operating wise, it was a kneel down job. As I am starting again, the plan is the raise the scenic boards up so I can sit to operate it..being nearly 50, not 35 when I started it, I’m future proofing it, sod kneeling and reaching in at 70!

[ISW]

I'm currently building a layout with a similar arrangement, 2 levels 350mm apart connected by 2 ramps (up and down). The lower level (storage) is 'flat', but in order to utilise the entire upper level for 'scenics' it has to has a slight gradient so that it 'runs under itself' after a complete loop. I managed to get the ramps to be 1in40 and 1in48, which isn't too bad for modern diesels.

 

Details of the ramps can be found in:

Ian

[40034_Nick]

Nothing better than watching trains climb a hill etc.. I dont really get a Helix thing myself, then again a don't really get fiddle yards on a static home layout when you can turn it into a freight yard.