If you want a fun and interesting model railway then you’ll want your trains hauling up hills and hurtling down. Here’s how to work out the space and gradient numbers needed to building inclines.
Watching tiny trains trundling around a model railway is fun but if the track is just flat it can get boring before long. Using cuttings to obscure them adds mystery helps but seeing your trains hauling up hills, now that’s something else!
On my N gauge Cornish-themed layout. I’m changing the track plan so my GWR pannier engines and wagons now climb up to the Tin mine by winding their way around a hill. The vertical action breaks up what would otherwise be a dull terrain track plan and adds interest for the viewer, will the little engine make it…
Why can’t trains go uphill?
Building inclines isn’t just a matter of titling some track upwards to the height required.
Given the small amount of surface area of a train wheel that comes into contact with the rails and the traction that can be bought to bear when climbing a hill, it’s really challenging for trains to go uphill. If the slope is too steep there won’t be enough traction to compete with the downhill drag the engine will stop or even roll backwards!
Watch James May elaborate and explain this.
It all boils down to ratios.
These ratios, also known as gradients or grades, measure the steepness of the slope. The steeper the slope, the more difficult it is for the locomotives to manage. They are typically expressed as the vertical distance (the ‘rise’) compared to the horizontal distance (the ‘run’), such as ‘1 in 50’. This can also be expressed as a gradient percentage. For example, a ratio of ‘1 in 50’ can be converted to a gradient percentage by dividing 1 by 50 to get 0.02, then multiplying by 100 to convert this to a percentage, yielding a 2% gradient. The greater this percentage, the steeper the incline.”
In the context of railways, an incline ratio of 1 in 50 means that for every 50 units of horizontal distance, the track height increases by 1 unit.
Where as a steeper ratio, 1:30 means the track raises for every 1 units for every 30 units of track length. (The units can be anything from feet to meters or even centimeters, depending on the context).
The more gentle the slope and lower the ratio, 1 in 60 for example, the easier it is for the train to climb.
As seen above, trains aren’t good at moving upwards so longer runs of track are needed to climb to greater heights.
On real railways, ingenious designs have been developed over time to provide the length of track required without the miles of straight track being needed. These include spirals that work their way around hills and mountains, zig-zags and horse-shoe designs.
Even so it’s still a challenge. In a discussion on this very subject on the Bachmann trains forum, Doneldon noted that building inclines to prevent trains from stalling and backsliding means giving “careful attention to track and wheel gauge, rolling stock clearances, transition curves, moderate grades, electrical integrity, precise coupler adjustments and adherence to correct weight for your rolling stock” (see original post here)
Did you know? The steepest prototype mainline railway in Great Britain is Lickey Incline, south of Birmingham, with a bonkers gradient of 1-in-37.7 (2.65%). The line through the Luxulyan Valley in Cornwall, which I’ll be featuring as a spur on my layout, reaches 1 in 37 in places but only for short stretches.
Thankfully, the ratios taking all this into account for model trains have long been known.
What is the recommended ratio for model railway inclines
The tried and tested and most common ratio used for model railways is a gradient or grade of 1 in 50. Or a 1cm increase in height over 50cm of horizontal travel.
You can push this a bit and have steeper grades of course but the consensus from experienced railway transport modellers is not to go beyond a ratio of 1 in 40. With 1 in 30 being the absolute maximum considered by modellers on Model Railway Forum and the Anyrail forum (here and here). Equally, a more gentle incline is obviously possible and will be easier for your trains to negotiate.
A 1 in 30 grade, by the way, equates to 3.33% – compare this to the 2.65% Lickey Incline figure above to get an idea of how models compare to the real thing.
Typical incline ratios for model railways
- 1:30 (3.33%) Absolute maximum
- 1:40 (2.5%)
- 1:50 (2%) Recommended
- 1: 60 (1.67%)
Working it out the distance needed
But what do these mean for building an incline, how do we convert that ratio into the length of track needed to climb up to a point and the distance required? Essentially, it’s just a case of multiplying the vertical distance to be travelled by the ratio factor chosen. As seen, for most cases, this should be 50.
Step-by-step guide to calculating a model railway incline distance
- Choose your measurement unit: Decide on the unit of measurement you’re going to use. This can be inches, centimeters, or any other unit you’re comfortable with. Just remember to use the same unit for all your measurements.
- Identify the desired height: Determine the height your train needs to reach. This is from the top of the rail to the track level on bridge on your model layout, remember to include enough clearance for your tallest rolling stock and space for the bridge elements under the track.
- Calculate the required length: Multiply the height from step 2 by 50 (for the recommended gradient of 1 in 50). The result will be the horizontal distance your track will need to run from the reach the desired height.
- Apply to your layout: Now that you know the distance, you can plan and lay the track accordingly with for your track to run the calculated distance.
If you want the track to climb from baseboard level to a bridge that runs over another section of track measure. On one of my layouts, for example, this will be 5cm. Multiple this by 50 and I need to start the incline 250 centimetres from the bridge, creating a gentle rise to the crossing.
In experiments, I’ve had modern locos pull approximately 10 wagons or five-passenger cars up such a grade. For longer / heavier trains, you’ll need to select a more gentle gradient – 1 in 60 or even 70 – and the distance will increase.
These calculations assume you have a height you want to reach and need to know the run distance you’ll need to get there. If you have a long section of track and am wondering high high you can climb over the distance, Rather than repeat some simple maths, take a wander over to the Credit Valley Railway Company which has written an excellent article on the calculations needed.
I’d love to hear about your inclines and track plans, drop a line via the contact page or add a comment below.
Happy incline hauling!
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> A final, personal, note: I spend a huge amount of time testing, photographing, writing and researching techniques for these articles and pay for all the running costs of MRE out of my own pocket. If you found this article useful you can support me by making a donation on my fund-raising page. Thanks and happy modelling, Andy.
Andy is a lifelong modeler, writer, and founder of modelrailwayengineer.com. He has been building model railways, dioramas, and miniatures for over 20 years. His passion for model making and railways began when he was a child, building his first layout at the age of seven.
Andy’s particular passion is making scenery and structures in 4mm scale, which he sells commercially. He is particularly interested in modelling the railways of South West England during the late Victorian/early Edwardian era, although he also enjoys making sci-fi and fantasy figures and dioramas. His website has won several awards, and he is a member of MERG (Model Railway Electronics Group) and the 009 Society.
When not making models, Andy lives in Surrey with his wife and teenage son. Other interests include history, science fiction, photography, and programming. Read more about Andy.