Skookum Drawing Takeoffs

The objective of this page is to determine whether a visually convincing model of the Skookum, a Baldwin 2-4-4-2, can be assembled using Roundhouse parts from their inside frame 2-8-0 Consolidation and their 3 in 1 kit aimed at producing either a x-8-0T or a X-4-4-0T in HOn3.

Noting the proposed service is important.  This engine will pull lumber consists out of Duncan Mills.  A 2-4-4-2 is desirable because of its combination of tractive power and the ability to navigate relatively tight curves.

HOn3 is already a deviation from the prototype which was a standard gauge engine.  I would expect had Baldwin produced a 3′ narrow gauge version of the Skookum, it would have been lower and shorter as was typical of narrow gauge engines in relation to standard gauge.

Here is a set of Skookum drawings.

Skookum7

Dimensions are visible.  I blew this drawing up to fill an 8 1/2 by 11 piece of paper.  Coincidentally, the drawing is close to HO as you will see from the takeoffs.

Skookum Takeoffs

My ruling dimension from the drawing is the wheelbase of the rear pair of drivers which is 66″ from the drawing.  I took off length using my digital caliper and it turned out to be 0.779″ on the drawing.  Dividing the 66″ wheelbase by 87 (HO) translated to a 0.759″ wheelbase at scale.  The actual wheelbase measured on the Roundhouse frame is 0.52″ which translates into 45.24″ at 1:1 scale.

So the separation between the drivers on the frame (45.24″) is undersized in relation to the prototype (66″).  I would expect the narrow gauge locomotive to be shorter.  But the rear drivers wheelbase in the models frame is only 68.5% of what would be expected from the prototype drawings.  Of course this wheelbase could be changed with quite a bit of hacking of frame, side rods, cylinder rods and other components.  I’m going to park that problem for now.

Overall wheelbase including tender is 662 1:1 scale inches which translates to 7.609″ in HO scale.  That is about the same as the 2-8-2 Blackstone Mikado.

Driver diameter is 46″ on the prototype which translates to 0.545″ at HO scale.  The drivers on the Roundhouse models are 0.443″ which translates to 38.5″ at 1:1 scale.  Changing the model’s driver diameter would be a major issue on the Roundhouse kits.  The kit drivers are 83% of the diameter of the prototype.  With smaller drivers, you would expect to see closer spacing (wheelbase).   Other dimensions are not far out of line.

The next photo compares the drive train of the Roundhouse 2-8-0 to the drawing of the Skookum’s drive train.  Given that the drawing is close to HO scale, the drivers and the driver spacing is small in relation to the prototype.  Of course we are looking at the Roundhouse Outside Frame.  The Roundhouse Inside Frame  anything would look even smaller although it would be the same length.

Plan-Actual1

Does this kill the concept of using the Roundhouse kits to build a 2-4-4-2?  No, but it will need to be a freelance locomotive.  Calling it the Skookum would draw hordes of deceased rivet counters out of their graves like zombies, all headed in my direction.  Visualize that scene for a second.  It runs chills up my spine.

The next photo shows the Roundhouse Boiler in relation to the Skookum boiler.  It is a bit shorter but given the fact the freelance 2-4-4-2 will have a shorter wheelbase, it will work.

Plan-Actual2

Getting the boiler out brought another issue to my attention.  The following shot compares the Roundhouse 2-8-0 boiler and cab to the boiler/saddle tank/cab from the 3 in 1 kit.

Plan-Actual3

Yikes!  What should be my smallest locomotive, the 0-8-0T, would be the tallest and possibly the biggest.  What was Roundhouse thinking?  I’m going to have to give the solution to this dilemma some thought.  I could use the 3-1 kit parts for bashes with other Roundhouse kits.  I could fabricate (scratch build) a shell for a 0-8-0T.  But it turns that locomotive not a much bigger project than I anticipated.

Another alternative might be to build a 2-4-4-2T Logging Mallet.  Something along the lines of this Booth Kelley Mallet, except as a 2-4-4-2T rather than a 2-6-6-2T.  Such an engine should have a chunky look.  The outside frame with its counterweights would give that feel.  And the cab/bunker looks a lot like the cab/bunker in the 3 in 1 kit.  Hmm.  But the tank is different.

bk6_1947_hansen

 

How about this 2-6-6-2T logging Mallet?

clover4meh

The boiler is a bit longer than the boiler in the 3-1 kit.  But there would be only four driver wheels rather than six.

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