The K-37 class are the rebuilt standard gauge 2-8-0s. The tenders were rebuilt by re-gauging the wheels within the original standard gauge trucks.
The K-27 class were delivered with slope back tenders, which were replaced by conventional rectangular tenders. Those rectangular tenders carried 4,100 gallons of water and 8.5 tons of coal, per the D&RGW folio sheet. This is what is behind 463 and 464 as they exist today.
The K-37 class tenders carried 6,000 gallons and 9 tons of coal, again per the D&RGW folio sheet. The K-37 tenders are a bit wider than the K-27 tenders.
I believe scale drawings have been made of both classes. John W. Maxwell once sold O scale drawings of both classes of locomotives. His drawings were later available from his son, but have not been available since his son's death.
Model Railroader magazine had scale drawings for all four versions of the K-27 - as delivered, as simpled with slide valves, and both versions of the piston valve equipped engines.
Charlie Mutschler
-30-