Freight Cars - SP Flatcars - Overview

The Southern Pacific by the early 1900s had a large proportion of flatcars with all of the lumber producing regions around California and Oregon.  Let's look quickly at some common SP flatcar types in service between 1940 and 1960.  (Roster info from Anthony W. Thompson's Southern Pacific Freight Cars, Vol.3 Automobile Cars and Flat Cars, 2004 Signature Press, Wilton, CA.)

A string of SP F-50-Series flatcars rolling back to Northern California for more lumber was a common view from 1920 until the late 1940s.

This is basically a list of the various SP flats that would be around on the SP during the late steam era which I've been able to start building models of.  I'll be filling in more data and photos in the future with blog posts, which this page will eventually link to.  Lastly at the bottom of this page I'll be covering basic ratios of how many cars existed in 1950 for each group of classes.  Enjoy!

Jason Hill

40'10" Flatcars

F-50-1/2/3 - "Harriman" Era Flatcars

These three classes of car were the first all-steel framed flatcars on the SP.  They were built with pressed steel 'fish-belly' sidesill reinforcements which make them look very unique and easily recognizable.

Most were out of regular service by 1950 but could still be seen in SPMW service.  I'm planning to get a model for these at some point, but as yet I don't have any photos ready to show.

F-50-4 - The last "Harriman" Era-built Flatcar.

The SP Common Standard's first straight-sidesilled steel flatcar was the F-50-4, which used a single Bettendorf I-beam centersill was built in 1910.  All of these cars were built by Bettendorf, using their proprietary design of underframe.  OwlMtModels has plans to make these kits in the future.

The 1910-1911 built PE 3474, OwlMtModels concept model for F-50-4 (incomplete).

The 1911 built SPdeM 5527, OwlMtModels concept model for F-50-4 (incomplete).

O&C 48950-49009 (60 cars) 11/1910, absorbed into the SP in 1928, reporting marks changed there after.
NWP 4350-4449 (100 cars) 1910
UP 10651-10770 (120 cars) 1910, delivered with sideboards
OR&N 14150-14329 (180 cars) 1910, renumbered to 50124-50329, OR&N cars subsidiary of UP.
SP 40420-40635 (216 cars) 11-12/1910
CP 39000-39143 (143 cars) 10-11/1910, absorbed into the SP in 1928, reporting marks changed there after.
PE 5060-5169 (100 cars) 1910-11, Renumbered PE 3400-3499 in 1913.
AE 3000-3015 (16 cars) 1910
SPdeM 5500-5563 (64 cars) 1911, delivered with sideboards. (Owned by SP, Leased to SPdeM Sub)
CP 39144-39343 (200 cars) 11-12/1912, absorbed into the SP in 1928, reporting marks changed there after.
SP 40636-40855 (250 cars) 10-11/1912
GH&SA 2100-22349 (250 cars) 9-10/1912
O&C 49010-49059 (50 cars) 1/1913, absorbed into the SP in 1928, reporting marks changed there after.
CP 39344-39483 (140 cars)  12/1913-7/1914
SP 40886-40985 (100 cars) 1-2/1914
PE 3554-3613 (60 cars) 1914

SP 41186, a later F-50-5, rebuilt with sideboards in 1954 for service in Texas. OwlMtModels concept sideboards.

Note: O&C and CP absorbed into the SP in 1928, reporting marks changed there after, numbers remained the same.


The SP changed the design of the underframe to use the two-beam centersills and switched to Ralston (not Bettendorf) for the construction of these cars.  OwlMtModels is now making models of this series of cars. 

Here's a short quote from  Tony Thompson's OwlMtModels' F-50-series blog.,"In fact, it is evident that all these later cars (F-50-5, -8, -9, -10, & -12) were built to the same fundamental design, because all were built to the same Common Standard specification, CSF-307. Thus the fundamental Harriman Common Standard design of Class F-50-4 continued in use for almost 20 years, justifying the use of the “Harriman” name for all these cars."  While, as Tony points out, continuing to call the post-1913 cars "Harriman" cars is justifiable, I'll drop calling them that in this list for brevity.

T&NO 22419, ex-LW car of the same number.  OwlMtModels F-50-5 model.

SP 40986-41458 (473 cars) 6-8/1916
SP 41459-41483 (25 cars) 8/1916
CP 39409-39410 (2 cars) 8/1916, to SP reporting marks in 1928, unclear if these were lettered SP with CP spelled out for tax ownership or if these actually carried full CP reporting marks.
NWP 4450-4499 (50 cars) 1916
LW 22350-22474 (125 cars) 6-9/1916,  to T&NO reporting marks with same numbers around 1928.
LW 22475-22649 (250 cars) 8,9/1916,  to T&NO reporting marks with same numbers around 1928.

Here's an early version of what the NWP cars looked like after delivery.  Later the lettering was arranged more like the SP cars.

F-40/50-6 and F-40/50-7

These two classes of car are strange in that they're built during WWI and used steel frames, but with trussrods instead of I-beam or C-beam centersills.  Most were built as 40-ton cars (F-40-6/7) but all had 50-ton capable underframes and bodies, only being limited by the  trucks used under the cars.

No accurate models for these classes have been produced, but I did kitbash a couple from Walthers/Train Minitures 42ft flatcar models, which are maybe 80% accurate: in that they are flatcars and truss-rod construction, but not much beyond that.

T&NO 23454, an example of F-50-7 class, stand-in built from Walthers/TM 42ft flatcar.

Many of these cars used second hand 40 and 50-ton trucks.  The cars upgraded with 50-ton trucks became F-50-6/7 class cars, which I cover in SP F-50-7 Kitbash Standins (Part 2) T&NO 23454

SPMW 810, another F-50-7, taken out of revenue service to Ready Flat assignment.

Because of these cars being a severe departure from the SP's other designs, do not think of these cars when I refer to the F-50-4 through -10, and -12 cars in general.  These were the weird WWI-built cars.


The SP returned to its own designed cars after WWI with the F-50-8 class cars.  OwlMtModels is now making models of this series of cars.

SP 38892, ex-PE 3666, OwlMtModels preproduction F-50-8 kit.

GH&SA 23500-23699 (250 cars) 1923, to T&NO reporting marks with same numbers around 1928.
PE 3614-3763 (150 cars) 1923, to SP 38840-38985 (146 cars) in 1951.


The F-50-9s continued the F-50-8 design cars into 1924 with additional cars for the SP and PE.  OwlMtModels is now making models of this series of cars.

SP 43745, ex-PE 30104, OwlMtModels Preproduction F-50-9 kit.

SP 42600-42899 (300 cars) 1924
PE 30000-30149 (150 cars) 1924, to SP 43691-43790 (100 cars) in 1928 & SP 39820-39869 (50 cars) in 1940.


The next design change happened starting with the F-50-10s being built with ARA U-section type trucks (brown) instead of the ARA T-section cast sideframe trucks (gray) used on all previous classes, starting with the F-50-4 (except for the F-50-6/7 'WWI cars').  OwlMtModels is now making models of this series of cars.

These later cars with U-section trucks and earlier cars with trucks replaced with new or secondhand U-section trucks during the 1940s and 1950s continued in SPMW service well into the 1960s and even the 1970s.

SP 39740, an F-50-10 class built in 1927, OMM 2003 kit.

SP 39520-39819 (300 cars) 1927
SP 42941-43090 (150 cars) 1927


Again, another follow-on class ordered the next year continuing the F-50-10 design of 1927.  OwlMtModels is now making models of this series of cars.  Some F-50-12s were built with second hand trucks, including arch-bar trucks for the first 5-10 years it would seem from some photographs.

SP 43216, an F-50-12 class built in 1929, OMM 2003 kit.

SP 43191-43690 (500 cars) 1928-29


The SP's last 50-ton flatcar was the F-50-16, built at the same time as the bigger F-70-7s in 1949.  I describe the process of kitbashing the model in SP 140234 (Part 1) - Kitbash of RC F-50-16 from F-70-7 blog post.

SP 140234, an F-50-16 class car, another model which isn't quite finished detailing.

SP 140000-140499 (500 cars) 8-10/1949
T&NO 24650-24749 (100 cars) 1949

Some of these T&NO cars were fitted with TOFC gear for use with 35ft trailers on the Texas Lines.  I have no need for such cars.  It would be challenging, but possible to kitbash one of these from various EspeeModels F-70-7 TOFC kit parts.

Stand-Ins for 40ft cars

Red Caboose "F-50-4" AAR flatcar.

RedCaboose/Intermountain has long produced this model, which is not correct.

Red Caboose has long made this 40ft AAR style flatcar, which is lettered and numbered for an F-50-4, which as can be seen above is a totally different looking class of car.  These models wouldn't be so bad if they're renumbered and class data changed to reflect the F-50-16 class cars built after the war.  The stake pocket locations over the trucks is also wrong.

Athearn 'BlueBox' 40ft flatcar.

SP 140195, a kitbashed Athearn Blue Box model that I did about 15 years ago.

Likewise, the Athearn 40ft flatcar from the 1960's tooling is not correct for the SP's F-50-16s either, but it's about as close as you can find for this model to be used as a stand-in.  The above model is one that I did about 15 years ago and redecalled at one point with the correct number series for the early 1950s.  Again, the stake pockets are not in the right locations and are oversided.

50'9" Flatcars


These were SP's first 50ft flatcars, the end sills were rather light, basically the same as the other contemporary F-50-series cars such as the F-50-10 and later -12s.

SP 43131, an F-50-11 kitbash using Tichy kits.  I'll be talking about this in a future blog.

SP 43091-43190 (100 cars) 1927


The F-50-13s used slightly upgraded endsills over that used on the preceding class from 1927, otherwise they were almost identical.

SP 43791-44090 (300 cars) 1929-30

52' Flatcars


The F-50-14 was the first 52' flatcar that the SP bought in 1937, an expanded version of the earlier F-50-11 and -13 classes from before the Great Depression.  These cars were ordered as the SP was gearing up with new engines and passenger trains, such as the Daylight, business was returning to the SP!

Early kitbash roughed out for an F-50-14 using Tichy Parts.  The 'fishbelly' center sill still needs to be added.

SP 49480-49678 (199 cars) 1937
SP 79500-79699 (200 cars) 1937
T&NO 24500-24549 (50 cars) 1937

Kitbashed Tichy flatcar with a heavy bridge timber load, the focus of a future blog.

70-Ton Flatcars

F-70-1 (52' Length)

SP 49679 (1 car) Feb 9, 1937, one test car built based on F-50-14 with upgraded trucks, etc. as testbed for future 70-ton designs.

F-70-2 (53' Length)

The F-70-2 design pioneered the use of the fishbelly sidesills and underframe combined with the 70-ton capacity.  These cars were the SP's take on the AAR standard 53' flatcars build during the war years and by certain pioneering railroad before the war.  All later 52-53ft F-70-series classes were based on the F-70-2.

SP 79700-79824 (125 cars) 2-4/1941 by SPE Sacramento Shops

F-70-3 (60' Length)

SP 79934 F-70-3 kitbash, I'll be doing a blog article on how to make this car soon.

The SP decided they also needed some 60ft flatcars for lumber service and industrial loading.

SP 79825-79954 (130 cars) 6-8/1942 by SPE Sacramento Shops

F-70-5 (53' Length)

The F-70-5 class has a few differences from the later F-70-6 and the preceding F-70-2 pilot classes.  Most notably in the endsills.  It should be possible to modify an EspeeModels F-70-6/7 and backdate it to be an F-70-5 or F-70-2.  While I'm not planning to do this right now, I'll probably hit on it during my blog post on the F-70-6/7s.

SP 79955-80254 (300 cars) 4-5/1942 by PC&F

F-70-6 (53' Length)

EspeeModels makes F-70-6/7 cars as undecorated kits.

These 500 cars were the first design ordered after the war, in which they also finalized the corrections from the earlier classes of 70-ton flatcars.  This class was followed within the year by the huge identical order of F-70-7s in 1949.

SP 80255-80654 (400 cars) 10-12/1948 by AC&F
T&NO 24550-24649 (100 cars) 1948 by AC&F

F-70-7 (53' Length)

 EspeeModels makes F-70-6/7 cars as undecorated kits.  EspeeModels bought the tooling to produce these cars from Red Caboose, which produced these cars for several years in the early 2000's.

Red Caboose/EspeeModels F-70-6/7 with kitbashed OwlMtModels Lumber Load on top.

The SP finally hit their stride to match post-war building boom with the huge F-70-7 class of 2050 cars!  Many were assigned to the lumber trade out of Northern CA and Oregon to the Bay Area and Southern California, including points east on the Sunset route.

SP F-50-Series car with OwlMtmodels Blackburn Sugarbeet "Rack" fitted on top.  (Early Concept Model Shown)

OwlMtModels #2302, production example of the new F-50-5/8/9  with 4-Board Blackburn Beet Rack.

It should be noted also that with the arrival of the F-70-7s in 1949-50, combined with the arrival of the G-50-20 and -23 composite GS gondolas for sugarbeet service, there was a rapid decline for the need of the F-50-4,5,8,9,10,12 class 40'10" flatcars in lumber and sugarbeet service using the Blackburn Racks.  These new arrivals precipitated the large number of F-50-series cars being moved to SPMW service in 1951, and well beyond 1956 as the F-70-10s arrived through 1953 into 1954.

Red Caboose/EspeeModels F-70-7.

SP 140500-142549 (2050 cars) 10/1949-4/1950

F-70-7 TOFC Conversions

EspeeModels sells these F-70-7 TOFC cars.  Some F-70-7s were modified in March 1953 for TOFC service with PMT trailers, most replaced in TOFC service with redesigned TOFC equipment installed on new F-70-10s in 1954.

EspeeModels F-70-7 with TOFC 'Daylight' PMT 22ft trailers. Modeler Unknown, J. Hill photo at NWP/SPH&TS 2017 Convention

On a side note, TOFC ramps were built at many SP stations to unload these trailers.  Bakersfield was one of the first outlaying stations to receive one in March 1953.  Los Angeles, SLO, and San Fransisco of course were the other early facilities built.  These TOFC cars early on ran in the 'Overnight' trains between LA and San Fransisco, also on the 'Valley Overnight' from LA to Fresno via Bakersfield.  I'll be building several soon... and obviously blogging here about the process.

F-70-10 (53' Length)

EspeeModels sells models of the F-70-10 cars. The SP's F-70-10s were unique from the F-70-7s in the all-welded sidesills and large bolsters extending above the level of the wooden deck.  I'll be finishing up the car below and posting a blog about it soonish.

EspeeModels' F-70-10 plain deck flatcar, this kit's not been completed.

SP 142550-143549 (1000 cars) 12/1953-7/1954 by SPE Sacramento Shops, some built with revised 1954 design TOFC decks.

The following 70-ton flatcar classes were built after 1960 which I am not going to concern myself with posting here.

Stand-Ins for 50ft cars

Athearn 50ft 'Blue Box' Flatcars

Athean's 50ft flatcar upgraded with wood deck by Chris Hollingshead in the 1980s.

The sister of the Athearn 40ft flatcar is the Athearn 'Blue Box' 50ft flatcar, which is several feet too short, and again doesn't have the classic SP spacing of the last two pairs of stake pockets over the trucks.  These are at best used as stand-ins until EspeeModels F-70-6/7/10s or OwlMtModels F-50-series cars can be acquired to upgrade the fleet with.

Life-Like/Tyco/Mantua 50ft Flatcar

SP 80247, F-70-5 stand-in.

I kitbashed this model of SP 80277 when I only had the basic ORER 1953 data to work from.  This was well before we had the wonderful SP Freight Car series from Tony Thompson, which revealed that I'd picked the wrong number series for my model!

I've since renumbered my model to be 80247, which is a better stand-in number for an F-70-5 series car.  Better operationally to have all the weird cars in one number series so you know they're weird when you go to put the lumber loads on them!

These cars are a slightly better starting point than the Athearn cars, in that they have a heavier sill over the trucks, which looks more like the F-70-series 52ft cars the SP owned.  The lower sill flange ends over the trucks, and needed to be added back on, however even this is a bit of a problem.  The flange should be there on the welded F-70-10s, but not on the F-70-6/7s which were riveted.  An F-70-10 shouldn't have the rivets... so in a way this model is taking cues from both the -6/7 and the -10 and mixing them up.  Again the stake pockets are not in the correct locations, so at best these are stand-ins like the Athearn model above.

Fleet Ratios

Lastly, let's look at these overall fleet numbers of general service cars in say, 1950.  This will be useful in calculating averages for a 100-car fleet.  Note this will not counting cars in assigned service, or specially equipped, which will skew the ratios locally and in the overall fleet depending where you are modeling.  Seasonal shifts also took place during lumber shipment and sugar beet harvesting seasons.

For easy of calculating, I'll be combining all the US cars together when calculating the fleet.  It is well documented in photos that SP and T&NO cars freely interchanged seasonally between the two roads, so SP modelers shouldn't forget the T&NO cars and visa versa when looking at larger fleet numbers.  This is your chance to get maybe one or two T&NO cars in your fleet!

F-50-1 = 16 T&NO, 32 SP
F-50-2 = 17 T&NO, 58 SP, 13 PE, 158 SPdeM
F-50-3 = 69 SP
Totaling: 33 T&NO (~0.5%), 172 SP cars (~3%)
This does not counting the SPdeM cars, which were international and also sold off to FCP in 1951, so they're not around much longer anyway.

F-50-4 = 16 T&NO, 172 SP, 32 PE, 51 NWP, and 25 SPdeM (Not counting survival of UP/OR&N cars)
F-50-5 = 35 T&NO, 220 SP
F-40/50-6/7 = 83 T&NO, 21 SP
F-50-8 = 166 T&NO, 146 from PE in 1951
F-50-9 = 440 SP (including ex-PE cars)
F-50-10 = 439 SP
F-50-12 = 492 SP
F-50-16 = 500
Totaling: 300 T&NO (5.1%), 2430 SP (& subs) (41.7%), 51 NWP (~0.9% if counted), 25 SPdeM (not counted)

F-50-11 = 95 SP
F-50-13 = 295 SP
Totaling: 390 SP (6.7%), obviously about 1:3 ratio of -11s to -13s)

F-50-14 = 50 T&NO, 344 SP
Totaling: 50 T&NO (~0.8%), 344 SP (5.9%)

F-70-1/2/5 = 426
F-70-6/7 = 100 T&NO, 2450 SP
Totaling: 100 T&NO (1.7%), 1876 SP (32.2%)

F-70-3 (60ft cars) = 130 SP
Totaling: 130 SP (2.2%)

Grand Total: 483 T&NO, 5342 SP flats, 51 NWP (oddly the F-50-5 NWP cars don't show in 1950), 173 SPdeM cars.
Combined Total T&NO & SP = 5825 <- This is the number we'll be using to calculate fleet percentages.

Post 1950 Additions:
F-70-10 (built 1953-54) = 1000 SP
Totaling: 1000 SP after 1954.

I am not counting the F-70-10 cars in our 1950 fleet, but assuming the additional 1000 cars are added to the roster, and no cars left the roster 1000/6825 = 14.6% increase in fleet size with the new F-70-10 cars - (This of course is not true as MANY F-50-series cars were retired or reassigned to special service between 1950 and 1954, so the fleet wouldn't increase by 15%, but more shift towards the newer 70-ton cars.)

The End

SP 6386 completes its run over Tehacahpi on a passenger assignment, as the XMUG (empty lumber) heads west out of town.

Hopefully this page has been informative.  It will become the hub page as I will be adding links in the page to the building blog articles for the various classes as I continue work on them.

Jason Hill


  1. Jason,
    Really interesting summary, despite I'm in N scale :)
    Thanks for your time
    Enzo Fortuna

  2. Jason, Looking forward to your kitbash blog on the F-50-16. I bought a couple of F-70-6/7s from the SP HS with one of them as the candidate.

    Rich Christie

  3. Hello Jason, Have you pulled your line of 3D printed parts and accessories from Shapeways? Thank.

  4. Jason, how much would you charge to build the F-70-7 TOFC flat and 2 trailers? My fingers just don't work to do these any more. I tried on a flat and one trailer and they weren't pretty.

    1. I still have several of the cars to build for LMRC. Haven't got to them in years, but need to. I was making good progress on several of those F-70-series cars but my 2013 eyesight issues knocked me off the rails on those projects.

      Once you see me make posts on building them here on the blog, ping me again. The photo in this post of the assembled and painted TOFC F-70-7 was one that was at one of the SPHTS Conventions. I don't know who the modeler was. I just took the photo!

  5. Hi Jason,

    Thanks for very informative page! It helped me find the right kind of flatcar for my project, but as it isn't made by anyone, looking forward to your update on kitbashing the F-70-3 (60' Length) flatcar. This is the one I need for putting SP-18 narrow gauge steam locomotive on flat as it is being ferried between Owenyo and Bakersfield for servicing. Thanks again for being so generous for sharing your knowledge - Andrew :-)


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