Tuesday, December 29, 2020

Modeling SP B-50-series Boxcars (Part 1) Pre-War All-Steel (B-50-18,19,20,21,23)

I eluded to modeling some of these cars in my last post about the Owenyo Branch (Part 4).

For many years I've not really dove into SP's all-steel boxcar classes.  I'll also say here at the beginning, that I'm by far an 'expert' on the details of SP boxcar classes and details.  For a more expansive listing of the details involved in modeling SP's Prewar Boxcar Fleet, at the bottom of this post are links to Tony Thompson's blog where he dives into more details.

So I'll just be looking at a few examples of cars that I have acquired over the last 20-odd years, and several in just the last year with an eye towards building a small fleet for my planned Owenyo Branch layout's needs.

At some point I may look into finding workable options for the Post-War SP All-Steel Boxcars, but not yet!

B-50-18 & -19 - Square Corner Post

The SP's pre-war cars remained at the 10ft Interior Height (IH) standard which the SP preferred because of various route height restrictions at the time.  There are only a few models produced which are correct for these two classes of cars because of the square corner post Dreadnaught Ends.

B-50-18 - 1936/37 Built

Stock R-T-R Red Caboose B-50-18 boxcar model, SP 32892.

  • SP 32770-33269 500 cars
  • SP 33270-33519 250 cars
  • SP 33520-34019 500 cars
  • SP 34020-34519 500 cars, Totaling 1750 cars

I have a couple of these Red Caboose models to use as examples of this class.  Wood lined with sharp 4/5 Dreadnaught Ends, Youngstown doors, and wood running boards. - Description excerpt from Anthony Thompson's Southern Pacific Freight Cars Vol.4 Boxcars.

B-50-19 - 1937 Built

SP 38542, B-50-19, redecalled RedCaboose B-50-18 R-T-R model

Essentially repeats of the B-50-18 class ordered only one month later.

SP 37840-38089 250 cars
SP 38090-38339 250 cars
SP 38340-38589 250 cars
SP 38590-38839 250 cars Totaling 1000 cars

I'm planning on either renumbering or trading with a couple friends to get one B-50-19, although having slight fleet imbalances don't really bother me too much as nothing says I *Must* have an exact proportional fleet representation.

B-50-20, -21, & -23 - Round W-Corner Post

These three classes are nearly identical in terms of basic body, so I will be grouping them together. 

Running Boards/Roof-walks

A side note here, these classes of car had mostly Apex metal running boards as-built (unless noted below), not wooden running boards.  I may address this later when I can unearth my stash of metal running boards.  Kadee and Tichy offer suitable pattern running boards for these models.  From my view point, changing the running boards, even on a "completed" and weathered model is not a hard thing to do.

B-50-20 - 1940/41 Built

SP 84550, B-50-20 from Branchline Yardmaster with Speedwitch decals, (roof is not attached yet).

SP 83240-83739 500 cars (CRECO or Superior Doors)
SP 83740-84239 500 cars
SP 84240-84739 500 cars Totaling 1500 cars

B-50-21 - 1941/42 Built

SP 82992, B-50-21 - Branchline Yardmaster Series car with upgraded decals

SP 81990-82489 500 cars
SP 82490-82989 500 cars (U.S. Gypsum running boards)
SP 82990-83239 250 cars Totaling 1250 cars
T&NO 54100-54599 500 cars (Creco or Superior Doors)
T&NO 54600-54849 250 cars Totaling 750 cars (2000 cars both SP & T&NO)

B-50-23 - 1942 Built

SP 96311, B-50-23 with Creco doors - Branchline Yardmaster with Speedwitch decals.

Built into 1942 when Pullman exhausted the supply of parts, ending the order at 1744 cars.

SP 95520-95863 344 cars
SP 96220-96919 700 cars * +
SP 96920-97619 700 cars Totaling 1744 cars

* first 600 with CRECO doors, rest Youngstown doors
+ First 500 Gypsum, remainder Apex running boards

Models and Modifications

SP 32892 - B-50-18 - Red Caboose

Here's a close-up of the Red Caboose square corner post Dreadnaught End.

These cars are distinctive because of their square corner post design.  Built in 1936, these cars are well represented by the IMRC/RC models using RR-39093-4 in my case here (SP 32892) in the post-war 1946 scheme with spelled out SOUTHERN PACIFIC and a tare date from Brooklyn, Oregon in 8-47.

SP 32892, B-50-18 by Red Caboose with square corner posts.

I'll probably do some basic upgrades on the model for my Owenyo Branch, just replace the plastic couplers with metal 58-head KDs and paint the UF FCR, before adding some weathering for this post-1946 repainted car.  The coupler boxes will need screws installed as well.

SP 38542's roof with simple brush and makeup weathering sponge work. This is before the 'salt weathering.'

This B-50-18, 32892 has been redecalled with Speedwitch decals to B-50-19, SP 38542.  I've been working on getting the roof on both it and 32891 weathered in preparation to do some 'salt weathering' experiments.  The two Yardmaster cars below will be getting the removable-roof version of these same experiments.  Should be some good fun!

Branchline Yardmaster Boxcars

The BLYM cars work nicely as SP '37 boxcars with a bit of work.

All my BLYM cars have some basic modifications.  The stock models expect the use of a pair of steel nuts as weight above the floors.  

Stock BLYM nut-weight bosses over the bolsters.

Modified BLYM with bosses ground down.

This is really not a good idea to comply with LMRC's standards for car center-of-gravity, which we try to keep as low as possible in the car.  I grind down the molded bosses for the nuts and use sheet lead (roof flange material) to bring the car back up to club standard weight for the cars rolling and center-of-gravity standard allowances.

SP 81992 - B-50-21 (Ex-SP 82992)

SP 82992 - Branchline Yardmaster

Now this car's been in the shop for a number of years.  Looks like I didn't quite get the alignment holes reamed cleanly on the A-end, which made the installation about 0.015" low.  This causes the gap just below the roof.  I'll be filling that with some strip styrene and touching up the paint.

The paint changes include replacing the SP with the post-1946 spelled out name from Speedwitch Media decals' D114 set.  This side of the car has a replacement door which is not as weathered as the rest of the car.  A moderate weathering coat and pencil chalk marks complete the look of this car.

For the Owenyo Branch this car will be right at home with the chalk markings.  "MC" is the initial code for Mojave.  This would make sense for a clerk at Bakersfield or Taylor Yard (Los Angeles), as the freight agent at Mojave put in a request for some home-road boxcars.

SP 81992 after adjusting the car number decal.

I've decided to renumber my nearly complete B-50-21 into another number series, as most of my other cars are in the more common 82000+ series... the 81990-series is right above the 50ft boxcars, which are normally thought of with the 81000-series cars.  So it's a rather interesting "gotcha" car number.  Also by changing this car's number it is now in the Apex running board number series not the US Gypsum series.  At some point I may change the running board too.

SP 96311 - B-50-23 (Ex-L&C 902)

BLYM repainting to SP B-50-23 with CRECO/Superior Doors

This car is one that I bought about 20 years ago when I picked up a number of foreign cars.  The L&C only had a handful of cars and this particular scheme is from well after my modeling era.  So this car is repainted and will be decalled for SP.  I had also considered decalling it for NYC using the Speedwitch Media.

SP 96311 with galvanized roof and gray painted roof boards.

I decided to model one of the SP's minority cars which were fitted with the CRECO/Superior Doors.  I'm planning to have a mix of all-steel SP boxcars for my Owenyo Branch, so having a car which doesn't have the standard Youngstown doors will be nice.

SP 96311 with gray galvanized roof, pre-'salt weathering'. color 'ripples' artifact from photo stacking.

The B-50-23, 96311 will be a fun car and shown here with some of the overall gray roof, before 'salt masking' and respraying with the standard Freight Car Red.  I'll be detailing the experimenting with the salt weathering in an up coming post.

The running board on this car should be replaced with a US Gypsum pattern metal version.  I will probably do this later when I uncover my stash of metal running board parts.  For now I'm leaving the wooden boards, it is an easy change later on.

SP 84550 - B-50-20 (Ex-C&EI 2)

This model was acquired and was damaged during assembly.  Make sure to ream the alignment holes in the body for the ends on the BLYM cars!  The upper connections over the doors folded up and broke.  The rest of the body was fine.  The broken pieces were glued back in and lightly sanded flush again.

A-end and left side view of the partly repainted C&EI 2 boxcar.

B-End and right side view of the partly repainted C&EI 2 boxcar.

The damage repaired, the car is now ready to be decalled, coupler installation, and some minor details replaced (stirrup steps). 

Finally ready to be decalled.

This car will probably become another B-50-21.  Speedwitch's decal set offers B-50-20, SP 82745 as a 'number-jumble' which can be directly applied to the model.  I generally prefer to mix the decals at least somewhat.  I decided to do one of the very early B-50-21s SP 81993.

Haha... gotcha!  I changed my mind, and numbered this car in the higher number series, avoiding another 82000-series car number.  I was wanting a bigger number spread in this group of five cars I'm working on.  Originally, somehow I ended up with three cars all in the xx99x series... how that happened, I don't know.  One of the pet peeves I have is non-random clumping of numbers on my models.  In this group of five cars I had 32991, 32992 (double ouch, consecutive numbers!), 82992 (ok, really? Two cars ending xx992?!), and the two completely new painted cars.  Sooo I went with SP 84550 for this model.

SP 84550 with most of the decals applied. pre-salt weathering. Dec 28, 2020 photo.

The SP 84550 is getting very close to doing the salt-weathering masking.  The right side capacity decals still need to be put on.  Note again the photostacking artifacts of the FCR not showing as the same color.  I think the camera's actually catching the duty-cycling of the LED lighting.

At some point I may change this car's running boards to Apex pattern metal ones.

Galvanized Roofs with Peeling Paint

I'm also wanting to experiment making the peeling paint effects on the next few cars with the salt-masking technique.

SP 96311 with galvanized roof and gray painted roof boards.

I removed the roof and painted it with StarBrand Weathered Wood.  I'll be doing some wood weathering on the running boards.  I'll be using the rubber cement masking on the wooden running boards and the salt-masking techniques on the steel roof panels.

Here's view of two stock roofs from BLYM '37 boxcars.

Painted with StarBrand Weathered Wood before applying salt masking.

The paint used on the galvanized roof panels tended to peel off after a couple of years.  Replicating this on the model can be done by painting the underlaying galvanized roofing in gray, then applying a small amount of water, followed by salt into the areas that you want to have the peeled paint.  After allowing the salt to dry for about a week, over-painting the roof with standard SP Freight Car Red will keep the paint from adhering to the salted areas of the roof.

Pre-Weathering Before "Salting"

Somehow my post from Dec 6 has not been posted until Dec 28!  So let's jam in a couple more roof weathering photos before I do the seal coat and try the salt weathering.

SP 38542 pre-salt weathered roof panels with my usual Apple Barrel painting techniques, with photo-stacking.

Another view of SP 38542, B-50-19's - Dec 28, 2020 photo

I went with the failures of the paint around the ribs.  This is medium gray galvanized color added.  Then rust sneaking in as the galvanizing is starting to fail too.  I'm not sure how much of this I'm going to continue with as these cars were built 1936-37 and I'm modeling 1949-1953... so these cars are really only 12-16 odd years old, I have to question how fast the paint will fail compared to the galvanizing will fail and how fast it will rust.

SP 84550, B-50-20 with one panel failing to the point of rusting.

Both SP 96311 and 84550 roofs trying some various techniques.

SP 96311's roof, I'm trying adding another layer of gray with cosmetic sponges.  We'll see how it goes from here.

Coupler Modifications

Easy coupler replacement with "Whisker" scale-head couplers from Kadee.

I've replaced all the standard Kadee 5 couplers with the scale-head Kadee 148 "Whisker" scale-head couplers.  I believe this will be my standard coupler on my regular cars for the Owenyo Branch layout.  I'm not sure yet if I'll be cutting off the coupler magnetic uncoupling pins.

In Closing

I'll probably do a separate post on the salt-weathering techniques in 2021.  Speaking of the end of the year... Thanks to everyone who's commented on the blog this crazy year of 2020!  Let's look quickly at the stats from the last year.

2020 viewer count.

This year there have been about 65k views of the blog.  Amazing... All-time viewers count since July 4, 2016 has now reached 220k!

Top post views in 2020.

Thanks again for another great year of enjoying blogging and I'm looking forward to doing new projects into 2021!  Happy New Year!

Jason Hill

Related Articles:

Plastic Options for SP B-50-12/13/14 class Boxcars

Modeling SP B-50-series Boxcars (Part 2) - Post-War All-Steel - Overview of classes, modeling links to Anthony Thompson's blog.

Owenyo "Jawbone" Branch Freight Car Roster Planning

Tony Thompson Blog Posts on SP Boxcars:

Modeling Freight Traffic: SP Coast Line, 1953-Part 9 - Various classes of SP boxcars

Choosing a Model Car Fleet - SP Boxcars Update - Roster data for SP 40ft Boxcars including post-war cars

Choosing a Model Car Fleet-SP Box Cars - Roster Data

Upgrading Older Models - Athearn Steel 40ft Boxcar to SP B-50-18/19 stand-ins. - I may actually try doing this with an old scrap paint job Athearn boxcar that I have kicking around here. Still have an extra B-50-18 partial set of the Speedwitch decals... 


  1. Thoroughly enjoy your outstanding contributions to our hobby!

  2. Outstanding work. Have you considered Kadee #153 (short center shank scale head) couplers instead of the #158s? The closer coupling looks better to me, but may give problems on smaller radii.

    1. Yeah, I've considered it on various cars in the past. However usually the "short" couplers end up being too tight for cars designed for "medium" length couplers. In the retooling of the OwlMtModels F-50-5+ series cars' underframe mold, I did move the coupler boss inward about 0.03". In some cases now it's almost too tight, but it still works. Also given the nearly 0.25" wide Kadee standard coupler openings, there is noticeably more swing and shortening of the coupler shank length as the coupler swings off.
      Also remember that prototype couplers did have several inches of movement with the draft gear buffers.


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