The Union Pacific Railroad's M-10001 was a diesel-electric streamlined train built in 1934 by Pullman-Standard with a power system developed by General Motors Electro-Motive Corporation using a Winton 201A Diesel engine and General Electric generator, control equipment and traction motors.

It was delivered on October 2, 1934, and was used for display, test and record-setting runs for the next two months before being returned to Pullman-Standard for an increase in power and capacity, following which it was placed into service as the City of Portland train.

The power car had 12 ft (3.7 m) added to accommodate a 1,200 hp (890 kW) V16 Winton diesel engine.

It was installed in Union Pacific's locomotive units built during 1935–36, after which twin engine designs became preferred.

After serving on the Portland-Seattle run it was retired in June 1939; the City of Denver trains needed more power and Union Pacific cannibalized M-10001 and M-10004.