The Canada Atlantic was ballasted with gravel quarried from various pits along the line, as were most railways of that period. So, it should be a simple matter to simply dig up some dirt from the right of way or from one of the quarries, sift out the big chunks and glue it down.
Unfortunately that turns out not to be true. The problem is twofold: a large constituent of the colour appears to be dust, and when you go to glue down the ballast, all this dust disappears, leaving just the sand, which is much darker than we want. Secondly, softer rocks decompose more readily and make up a larger constituent of the resulting sand. In this part of Ontario, those soft rocks include mica and quartz, which appear as sparkles and translucent white ankle turners when you examine the ballast closely.
This photo shows what I mean. The spoon contains real dirt from the Pembroke site, and behind it, you can see I’ve glued it to some track. If you click through to the full size image, you’ll be able to discern the mica and quartz.
So, the search was on for a good grayish additive or replacement. After scouting around the usual model railroad suppliers and realizing that getting even a tester is going to cost a fortune due to import fees, I began to think closer to home. Then, I thought, “what about grout?” a bag of which I happened to have sitting in front of my shed.
Now, a quick search finds I am not alone in thinking of using grout: others have tried it and some have enjoyed success. Tim Warris of Bronx Terminal fame suggests mixing grout with sand, and this sounds promising as the gravel is not uniform, and the sand would appear as some of the bigger stones.
Below is a test of about 50/50 grout and real dirt (My apologies for the quality of the photo: my iPhone keeps crashing any time I try to use the camera). While the grout is clearly too light, it does appear that I can control the colour nicely with this medium, and it also kills the shine and sparkle of those bits of quartz and mica. Because of the mixture of sand and grout, there does not appear to be enough cement to bond firmly with just water, and so, it needs some matt medium or glue to hold it down firmly.
So, this is the approach we’ll be taking for ballast on Pembroke. Grout comes in tons of colours, and I’m certain I will be able to find one to match my samples, or maybe a shade or two lighter.
Meanwhile, I’m itching to get back to the actual layout. Enough of this testing! Unfortunately, I still have to finalize the switch rod design, and that’s going to mean another two weeks of waiting for Shapeways.