#2647
Pennsylvania Railroad class S1
🇺🇸 United States ·built by Pennsylvania Railroad· from 1939· class of 1 American four-cylinder duplex 6-4-4-6 locomotive
3 photos from Wikimedia Commons · credits & licences
- 1. PRR S1: Gottscho-Schleisner, Inc., photographer· Public domain
- 2. Locomotive Pennsylvania: University of Southern California Library/California Historical Society· CC BY 3.0
- 3. Pennsylvania Railroad Class S1 No.6100 hauling the Liberty Limited eastbound in April 1941: PRR1944· CC BY-SA 4.0
what is it?
The PRR S1 class steam locomotive (nicknamed "The Big Engine") was a single experimental duplex locomotive of the Pennsylvania Railroad. It was designed to demonstrate the advantages of duplex drives espoused by Baldwin Chief Engineer Ralph P. Johnson. The streamlined Art Deco styled shell of the locomotive was designed by Raymond Loewy.
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 87 years ago, in 1939.
- Top speed is 1.9× a car on the Dutch motorway (130 km/h).
- At full speed it would cover Amsterdam–Utrecht (≈ 40 km) in 10 minutes.
- 5.4 MW is about 63 family cars (~85 kW each) flat out.
- Weighs about as much as 46 African elephants (~6 t each).
- 42.7 m long: about 9 cars parked nose to tail.
steam locomotive: Burns coal, wood or oil to boil water; the steam drives pistons that turn the wheels.
spec sheet
- built
- 1939
- retired
- 1946
- status
- retired
- number built
- 1
- kind
- Steam
- traction
- steam
- origin
- 🇺🇸 United States
- builders
- Pennsylvania Railroad, Altoona Works
- operators
- Pennsylvania Railroad
- top speed
- 245 km/h
- power
- 5.4 MW
- gauge
- 1,435 mm standard gauge
- wheel arrangement
- 6-4-4-6
- length
- 42.7 m
- weight
- 276 t
From the Wikipedia infobox and Wikidata. Blank means the sources don't say.
Sources: Wikidata Q452277, Wikipedia: Pennsylvania Railroad class S1 (CC BY-SA 4.0).Updated 2026-10-25.