Spline Construction

I have used spline roadbed in the past on the mid and upper levels of the railroad. For me, it is ideal for mountain railroading as it creates beautifully flowing curves, natural easements, and is narrow for steep scenery. As always, I start with reference to the track plan to lay out the curve, however, I am not married to it and often will use the spline itself to find the best fitting curve for the railroad in space. In this instance, the path suggested for the turnaround curve was rather awkward and tight so I elected to broaden it slightly.

Initial curve laid out with two masonite splines. Oakridge is out of the picture to the bottom right and the helix is in the bottom left. Also in this scene will be Salmon Creek and Pope and Talbot Lumber, which will fit against the backdrop. The view from a ladder is best to see the entirety of the curve at one time and make sure there are no awkward kinks or bends. 

After I have decided on the proper arrangement, I glue 2 or 3 splines together with wood glue. I have used 1/4" masonite ripped into 1" strips throughout the project. In this case I glued 3 layers together as the curve was manageable and easily accessible. 

Three layers of spline laminated together and drying with clamps. A good supply of spring clamps is necessary. 

When using two different types of subroadbed transitions are are necessity. For spline to plywood, it is best to cut a small key-slot for one of the layers to fit into. This ensures proper alignment and flow. Once all seven layers of spline are laminated, I will take more care into creating a smooth transition. 

We generally

raise or lower that first spline pair to their final elevations as we glue them.  Then, as we glue up the remaining layers, everything is in it's final orientation.  Our first few splines on my old layout were built flat, as you're showing, then we forced them up or down to get our elevation differences.  A couple of them delaminated during that forcing process, so we changed our approach.

Of course, that was with a recycled masonite woodgrain paneling that had one surface the glue had a hard time sticking to despite our sanding it, so delamination was a risk anyway.  Now, we use basswood spline and a hot glue gun, and things seem to go very well, although I have to improve the consistency of my basswood production.

Blair Smith

Timing of Orientation

Blair,

Your comment about timin of orientation (pre or post full lamination) is something to consider. One of the things that is difficult to see in the photos is that my benchwork itself is not flat but, in effect, holds a very similar grade that will be introduced with installation of risers. As such, the spline is not built completely flat, and so adding risers doesn’t but large amount of strain on the spline as I am really just fine tuning the grade. 

Your comment brings up a great point though for others working with spline on a grade to make sure they don’t build the spline flat and then muscle it into position as they may experience issue similar to those you describe.

Thanks for your comment!