Thursday, March 16, 2023

Modeling SP RSD-5 (Part 1) Horns, Indicators, & Stacks

About 15 years ago, on my original geocities blog, I posted about my Atlas/Kato SP RSD-5 conversions.  It's about time to bring the article up to date and repost it.  Special thanks also to Alden Armstrong, who shared his beautiful photos from the early 1950s!

SP 5301, 5339 & 5337 lashed up.

Atlas' RSD-4/5 model is about the only plastic starting point in HO scale.  Major issues that require buying nearly a whole new hood shell for the units include that the engines used paper air filters, instead of the louvered long-hood doors, tall battery boxes going all the way to the rounding of the short-hood, and dynamic brake slots and sheet metal fins over the end of the short-hood.

"Fixing" these issues is beyond the scope of this kitbash.  The correct long-hood with the paper air filters has been made available by Bowser, I believe as their RS-3 long-hood.  Several people have offered a new roof for the short hood with the dynamic notches, but you're still on your own for fabricating the covering sheet metal parts.

As most of the following models were already factory painted or already had the majority of the custom paint job done, the customer's didn't want to start over and completely rebuild the models from scratch.  Thus the level of rebuilding will be kept to details and added parts, not replacing the whole shell of the model.

Prototype Classes

First, let's look at the prototype engines, and their differences.

DS-114 (SP 5294-5307)

SP 5303 in Tiger Stripes at Taylor Roundhouse, Los Angeles, circa 1953-54 - Alden Armstrong photo used with permission

Super corrected models for SP RSD-5s of class DF-115 (SP 5294-5307) & DF-114 (5336-5339) had large "ash-can" spark arrestors installed and ran long-hood forward.  The DF-114 class, SP 5305-5307 were built as dual-control cabs and train indicators on both ends of the cab, but were designated as long-hood forward as the 'normal' direction.

Front right side of SP 5301 with orange end lettering, per photos

The DF-114s had vertically mounted headlights.  I stopped on these models about half way through doing the conversion, as the next step would be making the outer ring and plate glass cover for the pair of headlights.

I put La Belle crew in both sides of the 5301, and opened the windows, which was common on helpers and as these first generation engines had no air-conditioning.  A-Line photo-etched cab shades were used on these units, as they're about the only ones out there made from brass with the legs to survive being bumped.

Front left side of SP 5301.

I never got around to applying the diagonal "tiger stripes" decals to the fuel tank and lower ends of the 5301.   Perhaps someday I'll get around to it during the next rounds of detail upgrades.  I might get some class lights to put on the long hood too.  I should add that the plastic horn brackets got knocked off over the last 20 years of service, so those will need to be replaced at some point before I put the 5301 back into service on the Jawbone Branch.

5306, one of the three bidirectional RSD-5.

Not much is different on the last three DF-114s, except they were fitted with dual-control stands in the cab and train indicators on the short-hood end of the cab to display their identification when running short-hood forward.  They were to be used on stub-end branch lines, with no turning facilities, but mostly they were used as normal DF-114s in helper assignments, locals, and even showing up on the SD&AE.

DF-119 (SP 5336-5339)

Possibly Walong SP 5339 in original Tiger Stripes, shoving mid-train circa 1953-54 - Alden Armstrong photo, used with permission

The DF-119 class engines were unique in that they were fitted with large "ash-can" style signal lights (white) on both ends and water tanks for the turbo charger ahead of the stack, which the other sister classes did not have.

The SP 5337 was even a bit weirder in that when the engine was assigned to work out of Sparks it was fitted with snow plows on both ends, per photos in Strapac's Alco Road-Switchers book.

SP 5337's short hood end with plow and signal light.

I went ahead and built my 5337 as a black-widow version and as fitted for service out of Sparks, NV on the locals around there.  My engineer is resting his arms on the edge of the cab with the window open on his side of the cab.

Left side of the SP 5337.

The left side of the 5337 has its windows closed and sunshade collapsed down against the cab-side, so at least from this side the 5337 can be realistically used as an MU'd engine mid-consist or trailing engine.

DF-126 (SP 5494-5507)

SP 5498 (right) and 5294 (left) at Taylor Yard engine house, circa 1955-56 - Alden Armstrong photo used with permission

The later class DF-119 (5445-5448) & DF-126 (5494-5507) were built to run short-hood forward and didn't need the arrestor stacks as the exhaust system was improved.  The DF-119 & DF-126 classes were built in 1954 & 1955 respectively, so are after my modeling era.  These two later classes used the two sealed beam main lights (one is a gyra-lite) with the red square signal light above on each end.  The horns moved to the cab roof and were the same 3-chime style.

Kitbashing Parts

Now let's look at the different parts that are needed for all SP RSD-5s.

DF-114/119 Horn Bracket

Nathan P3, 3-Chime horn on plastic bracket

The problem with the plastic C-channel bracket that I used is that it doesn't survive a sharp bump without breaking off.  I'd probably do it again with a piece of bent brass sheet or structural shape.

Train Indicators

SP 5337's train indicators, only on the "front" of the engine's hood.

All of the long-hood forward engines (5294-5307, 5336-5339) were fitted with train indicators just in front of the cab.  The following classes (5445-5448, 5494-5507) were fitted with their train indicators on the short hood side of the cab.

SP 5305-5307 with dual controls and train indicators on both ends.

The 5306 has indicators on the short hood also.  The horn is still mounted on the long hood side of the cab.

DF-114/119 Spark Arrestor Stack

Scratch-built RSD-5 stack with PSC screen for SP 5337.

Originally, 20 years ago I was scratch-building the large stacks from styrene tube and strips.  In 2021, I did some drawings for OwlMtModels to offer two versions of these stacks for sale.  Contact OwlMtModels at sales at owlmtmodels (dot) com for specific ordering information and availability. 

SP RSD-5 3d printed stack with screen on SP 5339 with turbo tank to the left.

Or open-topped without the screen mesh, which could be made from PSC screen or other vendors' material.

New OwlMtModels 3d printed stack on SP 5339

DF-119 Unique Parts

SP 5337 with snow plows (both ends) and the signal light.

The DF-119 had two extra features not seen on any of the other three classes.  These units were setup a bit more for road-switcher assignments than the DF-114, which were bought for operations on Tehachapi grades between LA and Bakersfield, and the last three units were regularly used on stub-end branches without turning facilities at the ends.

Turbo Charger Expansion Tank

Top view of SP 5337 with expansion tank and stack - (Sorry for the low-res photo)

The turbo tank was made with styrene sheets.

The new stack with the turbo tank to the left.

Signal Lights

SP 5337 signal light made from DTW's "SP Ash-can" headlight.

I drilled through the back and lit the signal light.  The old MV lens were used with the backing foil removed.  I focused the light once the lens was in place.

In Closing

SP 5339 and 5337 sitting on the west wye switch at Owenyo.

I didn't get into changing the louvers to the paper filters or changing the short hood to model the dynamic brakes with the sheet metal fins.

Jason Hill

Later, I'll add related diesel modeling articles

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