Cab Forward Facts and Trivia
Cab Markings
What did those Cab Forward cab markings mean?
AC-4 | Class designation |
AC63 | Articulated Consolidation, 63 inch drivers |
24 24 | Cylinder diameter (front and rear) in inches |
32 | Piston stroke in inches |
475 | Weight on drivers in thousands of pounds |
SF | Superheated, Feedwater heater |
The Monkey Deck
|
Monkey Deck |
The Southern Pacific Cab Forwards had a platform immediately following
the smokebox of the locomotive (as shown in the figure to the right).
This platform was called the "
monkey deck. Smoke boxes were often
stained with rust from boiler water and boiler water treatment chemicals.
Because of its proximity to the stacks, the
monkey deck was often
stained with rust from boiler water too. Occasionally articulateds would
spew hot water and mud from their stacks. Most railroad employees were
aware of this fact. However, many hoboes thought the
monkey deck
was a good place to ride. After passing through tunnels or snow sheds,
hoboes riding the deck were either scalded or asphyxiated depending upon
how the locomotive was performing. The
monkey deck was not a
good place to ride on Cab Forward locomotives.
Southern Pacific Yellowstones
Not all Southern Pacific articulateds were Cab Forwards. Class AC-9 was made
up of 12 Lima built
Superpower, coal burning Yellowstones (2-8-8-4).
They had the same tractive effort of the Cab Forwards. They were numbered 3800
- 3811 and were used in the Southwest.
Cab Forward Classes
Class | Locomotive Number | Wheel Arrangement | Driver Diameter | Cylinders | Steam Pressure | Tractive Effort | Horse Power |
MC-1 | 4000-4001 | 2-8-8-2 | 57 | 26x40x30 | 200 | 85,040 | 4000 |
MC-2 | 4002-4016 | 2-8-8-2 | 57 | 26x40x30 | 200 | 85,040 | 4000 |
AC-1 | 4000-4016 | 2-8-8-2 | 57 | 22x22x30 | 210 | 90,940 | 4350 |
MC-4 | 4017-4028 | 2-8-8-2 | 57 | 26x40x30 | 200 | 85,040 | 4000 |
AC-2 | 4017-4028 | 2-8-8-2 | 57 | 22x22x30 | 210 | 90,940 | 4350 |
MC-6 | 4029-4048 | 2-8-8-2 | 57 | 26x40x30 | 200 | 85,040 | 4000 |
AC-3 | 4029-4048 | 2-8-8-2 | 57 | 22x22x30 | 210 | 90,940 | 4350 |
MM-2 | 4200-4211 | 4-6-6-2 | 63 | 25x38x28 | 200 | 65,900 | 3000 |
AM-2 | 3900-3911 | 4-6-6-2 | 63 | 22x22x28 | 210 | 76,800 | 3450 |
AC-4 | 4100-4109 | 4-8-8-2 | 63 | 24x24x32 | 235 | 116,900 | 5640 |
AC-5 | 4110-4125 | 4-8-8-2 | 63 | 24x24x32 | 235 | 116,900 | 5640 |
AC-6 | 4126-4150 | 4-8-8-2 | 63 | 24x24x32 | 250 | 124,300 | 6000 |
AC-7 | 4151-4176 | 4-8-8-2 | 63 | 24x24x32 | 250 | 124,300 | 6000 |
AC-8 | 4177-4204 | 4-8-8-2 | 63 | 24x24x32 | 250 | 124,300 | 6000 |
AC-9* | 3800-3811 | 2-8-8-4 | 63 | 24x24x32 | 250 | 124,300 | 6000 |
AC-10 | 4205-4244 | 4-8-8-2 | 63 | 24x24x32 | 250 | 124,300 | 6000 |
AC-11 | 4245-4274 | 4-8-8-2 | 63 | 24x24x32 | 250 | 124,300 | 6000 |
AC-12 | 4275-4294 | 4-8-8-2 | 63 | 24x24x32 | 250 | 124,300 | 6000 |
NOTE: Class AC-9 were Yellowstones (not Cab Forwards)
The Last Cab Forwards
- The last Cab Forward in revenue service was 4-8-8-2 4211 which hauled
freight from Oakland to Davis and then to Roseville with only a caboose
on November 30th, 1956.
- In November, 1957 4274 was brought out of retirement to make the last run of a Cab Forward over Donner Pass from Sacramento to Sparks and back.
- Cab Forward 4180, stored at Watsonville Junction, was hauled to the shops
for painting and preservation. On the way to a park in Oakland, inadequate
support timbers during a city street move resulted in a disaster and the
scrapping of 4180. Date unknown. Source Gunnar Henrioulle.
- In 1960 the last Cab Forward to be scrapped was AC-10 4243.
- On May 7, 1981 AC-12 4294 was designated a National Historic Mechanical Engineering Landmark.
No. | Class | F.M. Whyte | Gauge | Railroad Line | Location | Status | Builder Info | Notes |
4219 | AC-10 | 4-8-8-2 | 4'-8½" | SP | Oregon Rail Heritage Center, Portland, OR | operational | Baldwin #64310, 1942 | Tender only. Engine sold for scrap in 1958. Used as an auxiliary water tender for both SP 4449 and SP&S 700. |
4294 | AC-12 | 4-8-8-2 | 4'-8½" | SP | California State Railroad Museum, Sacramento, CA | display | Baldwin #70101, 1944 | Became the last Cab Forward built for the SP. Became the only surviving SP Cab Forward in preservation. |
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