Re: bring a cold engine up to steam much faster

I don't know about a full GPCS modification. But, the Grand Canyon and the Mt. Washington Cog Ry. have had lempor exhaust system modifications. The Cog is reporting on the engine which had this conversion is cut fuel consumption by a peak of 62% and this is using coal as fuel like the D&S. While those modifications mostly affect road operations, I think the redesigned blower ring and petticoat pipe (do they call it that as part of a lempor system? I don't know what else to refer to it as) for the lempor help even sitting in the yard. I think this is a likely route many coal fired engines may have to go in the future. I think it is an acceptable solution because unlike a full GPCS, the modifications can be made relatively inexpensively, non destructively and with little imposition on historical appearance (unless someone is looking in the smokebox).
Regards,
Trevor H.