I hadn't been aware of these specific follow-on orders, but the practice of smaller Canadian roads placing an order for cars identical to and immediately following one by a major Canadian road seems to not be uncommon: BC Rail did so as recently as 1979-80 with boxcars that were a followup to a CN series.

I can certainly see why the smaller roads might be interested in doing such things... there had to be a cost saving in terms of the builder already having the jigs on the floor, and workers that clearly understood construction sequences and challenges of any particular car build. Clearly the builders were willing to pass along some of the savings, which would result in such orders being more affordable for smaller roads.

It would be interesting to see how this sort of order was created... did the smaller road explore with builders to see what orders were in the books that they might be able to tack on to, or did the builders reach out to smaller roads on a regular basis to see if they might be interested in acquiring cars -- especially if the builder expected some downtime following said larger order.

Ian Cranstone
Osgoode, Ontario, Canada
lamontc@...