Tuesday, February 28, 2017

Modeling SP's Road Switchers (Part 2) - Medium Steam Engines

This is the second post of Modeling SP's Road Switchers, which I would classify as medium size.  In Modeling SP's Road Switchers (Part 1), where I covered SP 0-6-0, 2-6-0, 2-8-0, 4-6-0, and 0-8-0s.

In this post, I will focus more on the next group of engines heavier, primarily the medium sized Mk (2-8-2) type.  When these engines were built they were among the SP's biggest steam engines and were used in freight and some passenger service for the engines with 63" drivers.

The prices listed below would be what I would consider to be "Fair" market value for a model in good condition in February 2017 without DCC.  In most cases the low price would be for a model requiring a new paint job and the higher price what a model with minimal repainting would be "fair".

SP 2-8-2 Mikes

SP 3208, a Mk-2 class 2-8-2.  Photo from Eddie Sims Collection, used with permission.

The SP's smallest standard 2-8-2s were the 57" drivered engines of the Mk-2 and Mk-4 classes.  These two classes of engine outlasted the larger Mk-5 and -6 class engines.  The Mk-2s and -4s lived until 1954 and 1955 the various locals around Oakland, Tracy, Mojave, and San Jose.  They also show naturally up as heavy switchers around Oakland and Los Angeles.

SP Mk-2 Class - Sunset ($400-450) & Division Point ($900-1100+)

The left side of an Mk-2 Class from Sunset Models.

The right side of an Mk-2 Class from Sunset Models.

The Mk-2's were assigned to numbers 3200-3215.  These were built in 1911 with 57" drivers, converted to oil firing in 1912 and superheated between 1917 and 1919.  Several were rebuilt to Mk-4 specifications between 1929 and 1931.  Several of these engines lasted until 1954 and 1956, when finally replaced by GP9s in local service.

SP Mk-4 Class - Sunset ($400-450) & Division Point ($900-1100+)

Left side of Sunset Models SP Mk-4 with WSM 120-SC tender.

Right side of Sunset Models SP Mk-4 with WSM 120-SC tender.

The Mk-4s were assigned numbers 3216-3235.  These were built in 1913 and upgraded several times over the years.  The model shown will probably become SP 3203, a rebuilt Mk-2, which had the heavier frames and new cylinder block fitted when it was upgraded.  A previous owner tried to relettter it, scratching up the cabsides, which will require some additional work to fix.  Otherwise this is a smooth running engine.

Arizona & Eastern Mk-4 Version

SP 3237 - Eddie Sims collection

The left side of an AE Mk-4 from Sunset Models with an extra "120-C-2" also from Sunset from a 2-10-2.

The right side of an AE Mk-4 from Sunset Models with the corrected cylinders.

Five engines built for the Arizona Eastern (AE 901-905) were transferred in 1921 and 1924 and numbered 3236-3240, bumping five of the original SP 3236-series Mk-5s into the 3271-series. 

I talk more in-depth about the Sunset Mk-2 and Mk-4 models in my blog Correcting Sunset Models SP Mk-2 & Mk-4.

Update April 2018: I recently picked up an SP Mk-4 (non-AE version) which I'll be photographing and posting about here soon.  It will probably become the Mk-2 SP 3203 with a 120-SC-type tender.  The engine had the correct cylinders, so I believe firmly now that the two customer engines I blogged about above were a weird case where the previous estate owner swapped the cylinders to make the Mk-2 into a Pacific Lines Mk-2/4 with the upgraded cylinders, so I simply corrected that non-factory swap back to the original arrangement of parts.

SP Mk-5 & -6 Class

The Mk-5 & -6 class engines were built with 63" drivers for mountain passenger assignments and also soon down graded to medium freight service.  Many were assigned to the T&NO (Texas Lines) and models of these are available with the signature "Dog house" on the tender for the brakeman.  I will be focusing on the Pacific Lines Mk-5/6s which did not have the "dog houses" primarily the Balboa Models which were the more common models.  Alco Models imported 2-8-2s that were only correct for one SP engine and with major rebuilding a second engine.

SP 3269 - Mk-6 - ALCo Models ($350-400)

SP 3269 with the Elesco FWH and piping in front of the stack.  Ryan Dora model & photo, used with permission.

SP 3269 and 3270 were odd-balls among the Pacific Lines engines as they're fitted with Elesco feed water heaters mounted across the top of the smoke box in front of the stack.  Alco Models has imported a model of the SP 3269.  The 3270 also was weird in that it was fitted with a longer UP-style smoke box.

The rest of the Mk-5s and -6s were basically identical.  Some were fitted with "Sport" cabs with their slanted front wall, while others retained their square cabs.

Balboa Mk-5/6 ($325-450)

Returning helper SP 3259 drifts light through Bealville at LMRC, San Diego.

The Mk-5's were built by Baldwin in  1913 and assigned numbers SP 3236-3249, but in 1921 and 1924 the first five were moved to the 3271-3275 series.  Most were rebuilt over the years with higher boiler pressures and other changes like super heating.  Most were retired between 1951 and 1953, with one lasting into 1956.

SP 3270 was also built in 1914 and loaned to Baldwin for the Pan Pacific Exposition in 1914 It finally entering service in 1915 on the SP classified as a Mk-5.  Its first rebuild saw it equipped with Elesco FWH in Dec 1920.  The SP 3270 was retired and scrapped in 1953.

SP 3271-3275 were the renumbered SP 3236-3240 which lasted into the 1952-1954 time frame.\

SP 3276 & 3277 were originally built as the AE 906 and 907 in 1917 and retired in 1953 and 1952 respectively.  The AE engines were fitted with a smaller sand dome, more like what SP 2-8-0s were fitted with and the position of the bell and the sand dome were reversed from other Mk-5s.

The Mk-6 class were built by Lima in late 1914 and were numbered in the series 3250-3269.  The Mk-6's were rebuilt back and forth to coal and oil over the years.  SP 3269 was fitted in 1921 with a Elesco FWH, one of only two SP Pacific Lines engines fitted with this type of feed water heater.  Most of the Mk-6's were retired between 1953 and 1954, with one lasting into 1957.  Many lost their FWH's during the early 1950s.

SP 3251 - Mk-6 - with Sunset 120-C-2 Tender ($100-150) 

SP 3251, an Mk-6 that lived for a long time based at SLO, and used on the King City Turn.

This model shows the forward sand dome and "Sport Cab" with the 120-C-2 tender from a Sunset 2-10-2

SP 3259 - Mk-6 - with Sunset 120-C-2 Tender ($100-150)

The left side of SP 3259 with changes including replacement MDC "Harriman" cab andwalkway changes.

The right side of SP 3259 with Sunset 120-C-2 tender.

SP 3266 - Mk-5 - with Athearn-Genesis 120-C-6 Tender ($80-90)

The left side of SP 3266 with FWH above the 4th driver and Ath-Gen 120-C-6 tender.

The right side of SP 3266 with Athearn-Genesis 120-C-6 tender. (weathering not complete on tender)

Other SP 2-8-2s

The SP also had some non-standard Mikes that they acquired second-hand from other RR's.  I will cover them briefly.

SP Mk-10 - Ex-Minarets & Western # Engines (SP 3296-3297)

The Minarets & Western Lumber Company at Pinedale, CA (near Fresno) was abandoned in 1935.  SP bought the two small 51" drivered Mikes and quickly assigned them to heavy yard switching duties in Northern California, at Dunsmuir.

Westside Models (WSM) imported (Sam. built) models of this class.  These models are more common to find than the Sunset Mk-2/4s, but unfortunately are much less useful if you're modeling areas other than Northern California or Oregon.

SP Mk-11 - Ex-Newaukum Valley # 521 & 522 (SP 3298 & 3299)

SP bought two more Mikes from Wm. Shenker, an equipment broker.  These two engines came via the dealer Georgia Car & Loco Co. in November 1940.  Both had 51" drivers and were retired in 1953 and 1954 in Brooklyn, OR.

SP Mk-7/8/9 - Ex-EP&SW Engines (3300-3324)

SP 3305 running as an Extra.  Eddie Sims Collection, used with permission

The Mk-7/8/9s were built for the EP&SW at ALCo in 1913 with high square cabs, which was a signature of the EP&SW's larger engines including the Mt-2s (4-8-2s).  The Mk-7/8/9s were assigned numbers SP 3300-3324.  Around 1930 they came west and were rebuilt to burn fuel oil.

These engines were retired between 1950 and 1955.  Many photos of them can be seen around Los Angeles, Oakland and Altamont Pass in the post-WW2 to mid-1950s retirement dates.  In later years these engines were also fitted with large 120-SC-class "Whaleback" tenders off retired AC-3s and AM-class engines.

North Shore Lines imported models of these Mikes, which are rather expensive if they can be found.

In Closing

SP 3203 switching at Owenyo, 143 miles from Mojave.  Eddie Sims Collection, used with permission.

That covers the mid-range of SP's Steam Road Switchers.  I'll cover working on some of these models in more detailed blogs in the future.  Next time, I'll cover some of SP's bigger engines, and some of the heavier passenger engines.

Jason Hill

Related Links:

Modeling the Shasta - A Passenger Assignment for an Mk-5/6

Modeling SP Mail Trains (Nos.55 & 56), the Tehachapi - Also used Mk-5/6s near the end in 1954.

P.S. Update

Edit: A question from Andrew Thompson (below) was wondering about the lettering under the cab numbers.

Lettering under numbers reads "MK 63 24/32 221 SF" and rear corner "MK 6"

The data is translated as MK-type, 63in driver size, 24x32" cylinder bore, 221,000 pounds weight-on-drivers (used by the crew to calculate their pay rate for the day), S = Superheated & F = Feed Water Heater equipped. 

The S/F notes were only applied to the engines that were so fitted with the upgrades.  Most SP engines were Superheated during the depression at the latest, engines not upgraded were retired and scrapped.  Feed Water Heater systems were fitted on engines which were determined to benefit from the increased efficiency when pulling trains and recylcing exhaust steam to heat and inject the new tender water into the boiler.

More information can be found on my blog-page on the "Locomotives of the Southern Pacific (Spotters Guide Book) - Research page."  Enjoy!


  1. Jason,

    Which MK-5 & MK-6 were the last ones?


    1. Tom, do you mean the last in service, or the last built? The highest number were the earlier Mk-5s that were moved to allow the AE "Mk-4" which were not Pacific Lines engines to be slotted into the 3230-series. That little trick really makes the SP Mk-series engines a mess when you're looking at the Mk-5/6s mixed in the higher end number series.

  2. Hi, could you please enlighten me as to what the small letters are under the cab side numbers? (I would guess at loco class and possibly depot, but unsure.)

    1. Hello Andrew,
      Yes, the SP had standard lettering under the road number on their steam engines to specify the following information from left to right. Note that usually the engine class marks were at the cab rear with the dimensional data towards the front on each cab-side.
      So class data is as follows: Engine Type (GS, AC, MT, MK, etc)-Driver Size (in inches), Cylinder size (in inches) - "24/32" for example, Weight-On-Drivers in M's or thousands of pounds (231 for MK 6 class, for example) , S F (Superheated, Feed Water Heater, as applicable).
      The engine class would be standard form "MK 5", "GS4", etc. My decals are from San Juan Decals, which have all the applicable versions for all of SP's steam engine fleet.
      Note: I've edited a photo back into this post for you from my work on SP 3266's cab.


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