How to build a gentle gradient on an HO layout
Gradients let one line cross another, but steep or abrupt ones make trains stall or derail. Work out your rise and run first, then ease in and out of the slope.
- Time
- Half a day
- Difficulty
- Medium
- Cost
- Moderate cost
- Steps
- 7
- Checked
What you’ll need
- Tape measure and calculator
- Foam incline set or plywood with risers Search Amazon for woodland scenics incline set
- Spirit level Search Amazon for spirit level
- Foam glue and foam nails (for foam systems) Search Amazon for low temp foam glue gun
As an Amazon Associate we earn from qualifying purchases. The Amazon links go to search results, so you can compare what’s available.
Take care
- Use glue sold as foam-safe (Woodland Scenics sells a low-temperature foam glue gun for this); check the label before using any other glue on foam.
Step by step
-
Step 1: Do the sum
Gradient as a percentage = rise ÷ run × 100. A 4 in (10.1 cm) rise over 16 ft (4.87 m) is about 2%; the same rise over 8 ft (2.43 m) is about 4%. Woodland Scenics' 2% and 4% foam incline sets are made to exactly those figures.
Next: step 2 -
Step 2: Work out the height you need
Measure your tallest loco or wagon (and any overhead wire) plus the thickness of the upper track bed and some clearance. That's your rise. Divide it by the gradient you want to see how much run it takes.
Next: step 3 -
Step 3: Choose as gentle a gradient as you can
The gentler the slope, the longer the train your locos will pull up it. Test your longest train on a temporary ramp before you commit.
Next: step 4 -
Step 4: Ease in and out of the slope
A sudden change from flat to sloping track can lift a loco's wheels and cause derailments, especially long steam locos. Woodland Scenics sells "starter" pieces that rise from 0 to 1 in over 24 in for exactly this transition.
Next: step 5 -
Step 5: Build the incline
With foam systems, fix the incline pieces to the baseboard and to each other with foam glue and foam nails, then lay track on top. With plywood, cut a strip the width of the track bed and support it on risers at regular intervals.
Next: step 6 -
Step 6: Avoid curves and points on the slope
A curve adds drag, so a gradient on a curve is effectively steeper. Keep points off the slope if you can.
Next: step 7 -
Step 7: Check with a level and a train
Check the slope is even with no humps or dips, then run your longest train up and down several times.
Tips
- Keep gradients clear of baseboard joints.
Questions people ask
What gradient should I aim for?
As gentle as your space allows. Test with your own trains — what works varies with locos and train length.
Can I use set track on a gradient?
Yes; set track with moulded roadbed can go on an incline as long as the slope is smooth.
Sources
Checked 18 October 2026. We wrote this guide in our own words, using:
- Woodland Scenics: 2% incline/decline set (ST1410) (woodlandscenics.woodlandscenics.com)
- Woodland Scenics: 4% incline/decline set (ST1411) (woodlandscenics.woodlandscenics.com)
- Woodland Scenics: 4% incline/decline starters (ST1413) (woodlandscenics.woodlandscenics.com)
- Woodland Scenics: SubTerrain foam layout system (woodlandscenics.woodlandscenics.com)
- NMRA RP-11: curvature and rolling stock (2018) (nmra.com)
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Printed from locoho.co.uk/guides/how-to-build-a-gentle-gradient/ · Checked 18 October 2026 · General information only. Always follow the manufacturer’s instructions for your trains, track, controllers and decoders.