#1558
Southern Pacific class MM-2
🇺🇸 United States ·built by Baldwin Locomotive Works· from 1911· class of 12 American 2-6-6-2 (later 4-6-6-2) Mallet cab forward locomotives
what is it?
Southern Pacific Company's MM-2 class of steam locomotives was one of Southern Pacific's (SP) only classes of 2-6-6-2 "Mallet" type steam locomotives ordered and built as oil-fired cab forward locomotives. They were built in 1911 as compound-expansion Mallet locomotives by Baldwin Locomotive Works and entered service on SP beginning September 19, 1911. By 1914, they had all been upgraded with an additional leading axle making them 4-6-6-2 locomotives, reclassified from MM-2 to AM-2.
who runs it
base stats
Bars compare against all trains: 600 km/h (maglev), 1,700 seats; power, weight and number built on a log scale up to 20 MW, 1,000 t and 20,000 built.
fun facts
- First built 115 years ago, in 1911.
- Weighs about as much as 29 African elephants (~6 t each).
- Served for 37 years (1911–1948).
steam locomotive: Burns coal, wood or oil to boil water; the steam drives pistons that turn the wheels.
spec sheet
- built
- 1911
- in service from
- 1911
- retired
- 1948
- status
- retired
- number built
- 12
- kind
- Steam
- traction
- steam
- origin
- 🇺🇸 United States
- builders
- Baldwin Locomotive Works
- operators
- Southern Pacific Transportation Company
- top speed
- —
- power
- —
- gauge
- 1,435 mm standard gauge
- wheel arrangement
- 2-6-6-2
- weight
- 175 t
From the Wikipedia infobox and Wikidata. Blank means the sources don't say.
Sources: Wikidata Q7570316, Wikipedia: Southern Pacific class MM-2 (CC BY-SA 4.0).Updated 2026-10-25.