Another 2-6-6-2 question

[GN.2-6-8-0]

Has anyone removed or or been able to measure  the smokebox or more correctly its opening on the Bachmann 2-6-6-2? Would love to replace it it with a Cal-Scale brass Harriman style smokebox front which is advertised as 86".
Would like to replace the smokebox front in order to give it a more SOUTHERN PACIFIC look.

[J3a-614]

My copy of "Steam Locomotive Diagrams of the Chesapeake & Ohio Railroad" (ed. by Al Staufer) shows the H-4 smokebox outside diameter to be 90 1/2 inches at the boiler end; the front end is of the same diameter, but of course has a flat spot on the bottom, where the smokebox is also flattened to allow for the exhaust pipe from the low pressure cylinders to connect and swivel with the movement of the front engine.

Keep in mind this is what the prototype used, the model for a variety of reasons may not quite measure the same.

Hope this is of some help.

[pdlethbridge]

Maybe we could put a generic 2-6-6-2 on the wish list from Bachmann like these B&M engines they sold to the MEC

[J3a-614]

Very typical of the earliest Mallets, P.D., with the firebox partially over the drivers, and the use of saturated steam (note how the steam pipes come directly from the steam dome to the high-pressure cylinders).  Also note that this engine has a faily typical early Mallet valve gear arrangement with the very long lifting links mounted very high on the smokebox as a way to attempt to handle the swiveling of the front engine with minimal effect on valve events (something Mason Bogie locomotives had as well, becuase of that swiveling engine under the boiler), and that the valve gear is arranged to that the lifting links move in opposite directions for any valve adjustment (this was an attempt to balance the weight of the valve gear with itself and minimise power in moving it, some early Garretts also had this feature ).

The C&O engines, and the others that were apparently based on it, had the firebox totally behind the drivers, like most Mikados, Pacifics, Berkshires, and so on, along with some notable later articulateds, specifically N&W's A and the Lima C&O/VGN 2-6-6-6.  This arrangement gives a firebox more depth, and thus better combustion volume; as noted before, these relatively small engines (compared to N&W's very early Y class) were acknowledged to be very superior and were immediately copied by the N&W to the tune of something like 170 engines--and I checked some references I didn't check earlier, and found that the first 15 N&W engines also had the Walscharts valve gear.

That smokebox front, if the measurements are accurate, is about 4 inches too small in overall diameter, but that also works out to only 2 inches at any point along the circumfirence, so maybe it would be usable with a little strip of something run around the edge.  It would put the rivets around the edge in a little more than they should be, but would this be noticeable? 

Of course, the front would also require trimming at the bottom to match the flat spot in the smokebox there; one item that would help in restoring the rivets in that location is a product that's just out, was reviewed in RMC recently, had the rivets on a strip like a decal, you apply them before you apply paint.  Result is a strip of rivets without a bunch of hole drilling or sheet-metal punching.  Looks like a neat idea!

[GN.2-6-8-0]

Overall sounds like a fairly easy and  doable project, I have ordered the part from a LHS ,hopefully they can obtain it fairly quickly. Mounting the air pumps on the firemans side should be a easy modification , I also heard of the new decal type rivet detail and your point is well taken....thanks.

[Doneldon]

BTW - Have you ever wondered how they get those rivets from an ink-jet?