4-10-2 (Southern Pacific or Overland) Type Locomotives
The 4-10-2 was the logical evolution of the successful 2-10-2 and ALCO's push
for three-cylinder steam. The additional weight of the third cylinder and
valve gear in the front of a locomotive required a four-wheel lead truck.
In 1925 ALCO built two similar 4-10-2s and had the Southern Pacific and
Union Pacific try them out. On the SP, they called this wheel arrangement
"Southern Pacific". On the UP, they called this wheel arrangement
Southern Pacific liked the 4-10-2s and by 1927 had 49 of them. The Union
Pacific had moderate success and owned 10. The UP seemed to prefer their
In 1926 Baldwin built a three-cylinder 4-10-2 with a watertube firebox
which traveled around the country as a demonstrator model. It was numbered
60000 (the 60000th locomotive that Baldwin built. It didn't catch on
and was placed in the Franklin Institute in 1932 where it remains today.
This would be the only 4-10-2 that Baldwin would build. It would also be
in extremely good shape.
USA and Canadian Railroads that used 4-10-2 (Southern Pacific or Overland) Type Locomotives
Surviving Examples of 4-10-2 (Southern Pacific or Overland) Type Locomotives