[ Home ] [ Up ] [ 1:Saulselito ] [ 2: San Rafael ] [ 3: Tomales ] [ 8: Bully Boy ] [ 9: MS Latham ] [ 13: 2-6-0 ] [ 21: Stetson ] [ 40: NS 2-8-0 ] [ SP P11 Pacific ]

Southern Pacific P11 Class Pacifics

I became interested in this class when I discovered that the Northwestern Pacific had leased ten 4-6-2 Pacifics from the Southern Pacific just before and during World War II. At that point the NWPs standard gauge locomotive power was aging and being retired and the line began to rely more and more on the SP for its motive power. Stindt's book on the Northwestern Pacific lists the SP engine numbers but provides no photos or other data other than the dates engines 3100 through 3109 appeared on the NWP's engine roster.

While shopping on eBay I came across a book authored by Kenneth G. Johnson called 'Pacific'. This entire 134 page book is devoted to the 4-6-2 Pacifics of the Southern Pacific. It turns out these 10 engines were originally purchased from Baldwin in 1907 by the El Paso and Southwestern RR. They were added to the SP locomotive roster in 1924 when the EP&SW was absorbed into the Southern Pacific System.

Johnson's book identifies the SP locomotive class as P11 and provides builder numbers but no specifications. But the Johnson book provides a treasure chest of in service photos of engines from this class.

	This is a shot of SP 3100 with the original semi-circular Vandy style tender supplied by Baldwin. In this mid-1920s shot the headlight had been moved to the smokebox. Click photo for a larger image.
	Here's the same engine, 3100, with the other tender type seen on the P11 series. She's departing Santa Rosa on the NWP in 1938. Click photo for a larger image.
	Here's a 1947 shot of 3101 pulling the second tender style. Clearly from the diameter of its straight boiler, this is a light Pacific. Click photo for a larger image.
	This is a photo of EP&SW No 144 sporting the Baldwin semi-cylindrical tender. She became SP 3104. Note the original headlight location. This is the earliest in service photo for this class. Click photo for a larger image.
	This is an excellent side photo of number 3106 leaving San Jose in 1930. You can tell just how small this Pacific is by comparing driver diameter to the man in the photo. Click photo for a larger image.
	This is a nice front view of 3108. This shot taken at Santa Barbara in 1942 is from the WWII time frame. Note the hooded headlight to keep the headlight from being seen from above. Click photo for a larger image.
	Here's another war time photo of 3108. Click photo for a larger image.
	This small 1949 shot is of No 3109 at the Taylor roundhouse.
	And here's a look at the opposite side of 3109 shot at Mission Bay in 1938. Click photo for a larger image.

Builders Photos and Specifications

My reproduction of Baldwin Record No. 79 - Pacific Type Locomotives was published in 1914. It contains builders photos and specifications of the major Baldwin Pacific classes at that point in time. The first builders specifications in No 79 is for Class 12-38-1/4-D, a small straight boiler Pacific produced for the New Orleans, Mobile & Chicago Railroad Company. The production date is not given. This engine has an extremely similar appearance to the SP P-11 class, and is the only builders photo that I've seen that comes this close. It is the smallest Pacific in Record 79, weighing 335,000 pounds with its tender.

	This is the photo and description for the NOM&C RR engine. Note the straight boiler, cab design, dome placement, and headlight position. Click photo for a larger image.
	This is the specification sheet. Note that it had 69 inch drivers and a 7,000 gallon tender as standard equipment. Click photo for a larger image.

In comparing the above photo to the P-11 photos, focus on ES&PW No 124 which became SP 3104 as that's the earliest photo of an engine in the series. In later photos SP modifications to headlight placement, cab windows and other features become apparent.

The following photo and specifications are for a significantly different subclass of Baldwin Class 12-38-1/4-D. Number 908 was a Pacific built for the Southern Pacific about the same time. It shows differences in dome placement and in a number of other key areas. Based on photos in the Johnson book, it is likely this is the eighth of the original 22 engines that served the SP's Texas and New Orleans subsidiary. Originally numbered 900 through 921, these engines were renumbered to 600 through 62. An additional 15 Pacifics were added subsequently to the renumbering filling the 622 through 633, and 650-652 slots in the SP roster. These 37 engines made up SP class P-5. I'm including these builders photos in the P-11 class because I believe the P-5 Vandy 9,000 gallon tenders are similar to the Vandy tenders ordered with some of the P-11s. The P-11s had one less cylinder course, reducing their capacity to 7,000 gallons.

These engines were nearly 50,000 pounds heavier than the P-11's, tipping the scales at 382,000 pounds with tenders. They also had 73 inch drivers. Faced with a request from the NWP for leased Pacifics, I believe the P-11s were chosen as they could run on 70 pound rail. The P-5s were both heavier and with their larger driver diameters able to operate at hire speeds. The speed would be an advantage on the SP main lines, but was not an advantage on the NWP's lighter trackage and many curves.

	The builders photo and specification sheet is for SP 908. These engines assigned to the T&NO subsidiary were renumbered to 600-621 when added to the SP roster. Click photo for a larger image.
	They sported a half cylindrical Vandy style tender similar to those shown in some of the class P-11 photos. Click photo for a larger image.
	This is an in service shot of SP 901 taken at Welch, La in April 1919 four years before renumbering to 601. Click photo for a larger image.

Bashing the Engine

Given the 69 inch driver size, there is really only one engine choice for bashing this engine in 1/29, the Aristocraft Pacific. I own three Aristo Pacifics. Two are available for bashing. But I see a number of potential issues with an Aristo Pacific bash.

	The drivers at 2 1/2 inches scale to 72.5 inches in 1:29. That's slightly oversize for this engine but it is as close to a match as I'm likely to get. Driver spacing on the Aristo Pacific is near perfect. And it sports Walschaerts valve gear like the prototype.
	The Aristo Pacific has a wagon top boiler with a significantly larger diameter, consistent with it being a heavy Pacific. Given the smaller straight boiler of the P-11, I'd need to fabricate a new boiler.
	The Aristo Pacific tender is the wrong style and too long. I'd probably build a new tender and sell my Aristo tender on eBay.
	The Aristo Pacific cab might work if bashed. Otherwise a new cab would need to be fitted.

There are likely to be a number of other issues once I have dimension takeoffs

	I suspect the Aristo Pacific is too long and will need to be shortened.
	I suspect the cylinder diameters are too large. Once the variance is known, it will be apparent whether modifications will be necessary.

I'll add more information once I've had the chance to do takeoffs.

Bashing the Tender

This engine series was seen with two different classes of tender. Most if not all came from Baldwin with 7,000 gallon semi-cylindrical tenders. Some photos of these tenders can be seen in the above engine shots.

This is a side shot of the tender after the SP had made modifications to the coal bunker for clear vision rearward. These tenders were distinctive in that they had Andrews trucks with unusually high arches in their side frames.

Click photo for a larger image.

While the photos show two tender styles for the P11 class, the tender choice is clear to me. This is a really unique tender that will set the completed engine/tender combination apart from the crowd.

I'll look at the possibility of bashing the Aristo tender. But it may be necessary to scratchbuild the tender.

Southern Pacific P11 Class Pacifics

Builders Photos and Specifications

Bashing the Engine

Bashing the Tender

(c) 2007 Iron Horse 1:29