Southern's first batch of Ps4s were built by ALCo's Schenectady works in 1923, builder's numbers 64852-64863. The Southern assigned these numbers 1375-1386. Many more groups were delivered by Schenectady, to fill in numbers 1366 to 1392.
ALCo's Richmond works built 1393 to 1404 in 1926. These were the first painted green. The green engines proved to be very good for public relations. As a result, the rest of the Southern's passenger fleet was repainted into green. The 1926 engines were also the first with the Worthington feedwater heater. 1401, on display at the Smithsonian in Washington DC, was one of the 1926 batch.
In 1928, Baldwin delivered the last 5, numbers 1405 to 1409. They were very similar to the 1926 engines, except that they were built with Walscharets valve gear. By 1929, the rest of the Ps4s had been converted to Walscharets from Baker. Also 1409 was equipped with a Coffin feedwater heater. It was later converted to a Worthington type heater. And the tenders on the Baldwins were the same type as the earlier Schenectady engines, not like the huge tenders behind the 1926 engines.
Marlboro's model represents the 1926 engines. With a USRA tender behind it, it can be one ot the 1928 engines.
Cylinders: 27 x 28 inches
Drivers: 73 inches
Weight (in working order): 138 tons
Boiler Pressure: 200 PSI
Tractive Effort: 47,500 lbs
Grate Area: 71 sq. ft.
Heating Surface: 3690 sq. ft.
For a bunch of pictures, go here:
http://southern.railfan.net/
And navigate to the steam section of the photo archives. Many photos of different members of the class.
The Crescent Limited was painted in the two-tone green scheme in 1929, after the last of the Ps4s arrived. Before that it had been a very dark color, probably a dark pullman green. Lettering was probably gold before '29 and it stayed that way afterwards. The train's name was shortened in 1938 to just "The Crescent" and they started dieselizing it in 1941. The Southern only handled the train from Washington to Atlanta. The Pennsy took it north of Washington, the L&N took it from New Orleans to Montgomery, and the A&WP and WofA took it from Montgomery to Atlanta. One of the locomotives at the museum I work at was built to haul the train on the Atlanta-Montgomery segment.
Cheers,
Ben