The ALCO PA series is a type of six axle 2,000 hp diesel locomotive built between 1946- 1953. The engines were bought by 17 different railroads, including some being bought by the Sao Paulo Line in Brazil.
The ALCO PA was designed and tested near the end of WW2 in an effort to be ready for the post war market. This would also be the first use of the 244 engine in a mainline locomotive. The test engines (an A-B-A set) were sent to the Santa Fe in Warbonnet scheme.
The PA would be developed into the PA-1 and PA-2 with a proposed PA-3 that never went into production. Minor differences in mechanics were the only real differences between the PA-1 and PA-2. Internally the PA-2 contained a water cooled turbocharger which was added to earlier models during overhauls.
The PA series resembled its smaller cousin the FA a lot. Both had long, straight flat tipped noses with the headlight in a square, slitted grill. The headlight also varied depending on the road. D&H engines usually sported the upper grill light and a smaller dual bulb light below it.
The use of the untested 244 engine lead to the demise of the locomotive. Over time the engine wore out and became extremely unreliable. ALCO later supplied a 251 engine but was too late in doing so. The PA also failed to make a foothold in the passenger unit market that was dominated by EMD E-series engines. Also ALCO's partnership with GE would end leaving ALCO high and dry in the loco market.
Today out of 297 units (including B units) only 5 A units survive.
No. 600 in Brazil
No.16 and No.18 were resold to the US from Mexico. #16 is currently under restoration at the Museum of the American Railroad. No. 18 was sold to Doyle McCormack and is restored to appear as Nickel Plate No. 190
No. 19 is operational and is kept at the National Museum of Mexican Railroads in the Southern Pacific Daylight colors.
In a 1968 issue of Trains Magazine the ALCO PA was named "Honorary Steam Locomotive". This was because the locomotive was prone to having severe turbo lag that would send massive plums of black smoke into the air, similar to a steam locomotive.
Between 1947-1949 an Alco PA diesel was built to haul the first American Freedom Train all around the nation to celebrate the end of World War II. After its days on the Freedom Train, the locomotive was sold to the Gulf Mobile & Ohio Railroad and numbered 292 but sadly the locomotive was eventually scrapped in 1960.