Concrete Sleeper Track

I have recently laid some track with concrete sleepers using materials I purchased a couple of years ago from C&L Finescale in the UK.

Although intended for 4mm OO scale modelling, the size and spacing of the C&L sleepers are pretty close to Sn3.5 scale.  The sleeper spacing (pitch) is 10 mm and, although I normally space timber sleepers at 12 mm, the closer distance doesn't look wrong.

I purchased ready made track which included Peco Code 75 rail.  As I prefer weathered rail, I replaced the rail with Micro Engineering Code 70 rail.  Code 83 would also fit as the base of the rail is the same as Code 70.

C&L also sell the concrete sleepers on their own, which would be the way to go if you want the look of weathered rail.  

So far, I have completed just under 2 metres of track with the concrete sleepers.  The first section was time consuming, as it is on a very tight curve (600 mm radius) and I wanted to make sure the curvature was even to avoid any tight spots.  For this section, I glued the sleepers, which come joined in groups of 8, to the MDF roadbed using PVA glue.  I 3D-printed a guide strip which fitted inside the simulated Pandrol clips, to maintain even curvature.  Even though I pre-bent the rail to the required radius, I was quite difficult to slide the rail into the sleepers and I found the maximum workable length was about 20 sleepers at a time.  So, I had to cut the rail into shorter lengths for this bit.

Once I got into the straight track, it became much easier.  One technique which worked was to slide both rails into one group of 8 sleepers, then clamp the completed end of the track section onto my workbench with a scrap of plywood on top of the rails.  Then, I could easily slide the remaining groups of sleepers onto the 2 rails.

At this stage, the straight track isn't glued down, but I intended to apply dabs of PVA glue every few sleepers to hold it in position until ballasting.

It is essential remove any burs from the rail ends before assembling the track.  Also, it is necessary to cut the small joining pieces between the sleepers on one side for curved track.  Unlike normal flexible track, there are no gaps in the sleeper moulding.

One slight annoyance is the tops of the sleepers have raised lettering moulded in which says "COSTAINS", which is a UK manufacturer of real concrete sleepers.  As my layout is close to eye level, the lettering is not obvious, but it could be filed or sanded off if necessary.

C&L Finescale also make timber sleepered track with suitable sleeper size and spacing.  However, it is only available with bullhead rail (not flatbottom) so it is not usable for WA modelling.

3D-Printed Sn3½ Flexible Track

As an experiment, I recently tried 3D printing some sleepers for correct-scale Sn3½ track, using a similar principle to commercial flexible track.  I used the Makerbot Replicator printer which we currently have at home on loan, using a chocolate brown filament so the basic colour is about right.

It seems to work fairly well, although it would be a bit time-consuming printing sleepers for a basement-size layout.  For a modest layout, though, it appears to be a feasible proposition.  

The photos show the track with Code 70 rail (weathered, from MicroEngineering) but code 83 would fit too as the dimensions of the base of the rail are the same.  The tops of the sleepers have a textured finished from the printing process rather than the fake woodgrain on commercial track.

3D printed track with handlaid track in the background.
Note: I don't recommend use of unsupported MDF as trackbed
as it will inevitably sag - this is just a temporary arrangement.

The longest length which will fit in the printer is 18 sleepers @ 12 mm spacing which equates to 216 mm of track, so about 4 lengths would be required for a yard of track.  Printing each length takes just under one hour.  It may well be possible to print several lengths at one time side-by-side which wouldn't save much time but would save on trips back and forth to the printer.

Computer rendering of the sleepers.

As for cost, the cost of the plastic material works out to about $6 per yard, plus the cost of the rail of course (not including any costs for the 3D printer itself).  As a comparison, the NorthEastern scale lumber which I have used in the past for handlaid track costs about the same.

I also 3D-printed a jig to make it easier to insert the rail by keeping the sleepers parallel to each other so the rail slides in relatively easily.  So far, I have made about 1.5 metres of track.  

The 3D design could be changed to print straight track or fixed curves of any desired radius rather than having "flexible" track.  For example, if laying parallel tracks in a yard it could be easier to lay lengths of straight track to avoid the inevitable "wobbles" with flexible track.

Handlaid Points

The latest project on my workbench is a No.6 left hand point.  This one uses Code 83 rail (equivalent to 82 lb/yd rail in S scale).

Construction follows the same techniques I have been using for well over 30 years, with real wood sleepers and gluing the rail down with Pliobond adhesive.

Although I usually use Northeastern 12" x 6" HO scale lumber for the sleepers, this time I used precut On3/On2½ "switch ties" by Mt Albert Scale Models in Canada (available from The Railcar near Newcastle, NSW).  The thickness of the Mt Albert sleepers closely matches the On2½ flexible track and points available from Micro Engineering.  Prior to construction, I stained the sleepers with potassium permanganate solution.

The sleeper size and spacing of the Micro Engineering On2½ flexible track and points are just about spot on for Sn3½ track, except that the sleepers are 4-5 mm too long, but that is fairly easily fixed by trimming the ends of the sleepers.  Micro Engineering only makes #5 points in the On2½ range, so handlaying is the only option for other types other than converting HO points "sleeper by sleeper".  They do make a "kit" for No. 6 points consisting of a cast metal frog and machined blades, which could reduce the time and skills needed for handlaying.