Data from 1929 Pere Marquette Locomotive Diagram book supplied in May 2005 by Allen Stanley from his extensive Rail Data Exchange. (Thanks to Chris Hohl for his 5 May 2022 email sorting through the various differences among the superheated Pere Marquette Chautauquas.)
This program superheated the A-4 and A-5 Atlantics and created a common class. All had arch tubes, but by 1929 only 392-394--the first A-4s to be delivered in late 1901-- had three. Even that trio had different areas with 392 showing only 17 sq ft (1.56 sq m) and the other two 22 sq ft (2.04 sq m). The others all had four, which added 24 sq ft (2.23 sq m) to the firebox heating surface.
Hohl pointed out that after their superheater upgrade, all A-4s and A-5s rolled on 73" drivers and all but two (395 and 398) had 19" diameter cylinders. One A-4 subclass of road numbers 377-381 retained the original tender, which carried 10 tons (9.1 metric tons) of coal and 5,000 US gallons (18,925 litres) of water. Road numbers 382-389, 399-394 (A-4) and the A-5s trailed the larger tenders shown in the specs. Two more--391-392-- held 15 tons of coal but 4,500 gallons (17,033 litres) of water.
Data from "Brooks Pere Marquette Chautauqua Passenger Locomotive", Railway and Locomotive Engineering (June 1901), p. 234. Builder info from B.Rumary, 25 Kingscombe, Gurney Slade, Radstock, BA3 4TH, ENGLAND and Jeremy Lambert as supplied by Allen Stanley in March 2004. (Thanks to Chris Hohl for his 5 May 2022 email noting the overall length and supplying a link to the R&LE report.) Works numbers were 3778-3782 in February 1901.
These relatively low-drivered Atlantics (called "Chautauqua'" by Brooks) were fitted with "Improved" Belpaire fireboxes; they were part of a larger order delivered by Brooks in 1901.
The class operated in Michigan until the late 1920s-early 1930s. 397 was scrapped first in June 1928, followed by 399 (December 1928), 398 (September 1929). 395-396 lasted another 5 years before facing the torch on 13 April 1934.
| Principal Dimensions by Steve Llanso of Middle Run Media | ||
|---|---|---|
| Class | A-4 / A-5 superheated | A-5 |
| Locobase ID | 6550 | 4131 |
| Railroad | Pere Marquette (PM) | Pere Marquette (PM) |
| Country | USA | USA |
| Whyte | 4-4-2 | 4-4-2 |
| Number in Class | 17 | 5 |
| Road Numbers | 377- | 395-399 |
| Gauge | Std | Std |
| Number Built | 5 | |
| Builder | shops | Brooks |
| Year | 1901 | |
| Valve Gear | Stephenson | Stephenson |
| Locomotive Length and Weight | ||
| Driver Wheelbase (ft / m) | 6.67 / 2.03 | 6.67 / 2.03 |
| Engine Wheelbase (ft / m) | 27.67 / 8.43 | 26.33 / 8.03 |
| Ratio of driving wheelbase to overall engine wheelbase | 0.24 | 0.25 |
| Overall Wheelbase (engine & tender) (ft / m) | 51.35 / 15.65 | |
| Axle Loading (Maximum Weight per Axle) (lbs / kg) | ||
| Weight on Drivers (lbs / kg) | 90,000 / 40,823 | 83,000 / 37,648 |
| Engine Weight (lbs / kg) | 150,000 / 68,039 | 142,000 / 64,410 |
| Tender Loaded Weight (lbs / kg) | 120,000 / 54,431 | 98,000 / 44,452 |
| Total Engine and Tender Weight (lbs / kg) | 270,000 / 122,470 | 240,000 / 108,862 |
| Tender Water Capacity (gals / ML) | 6080 / 23.03 | 4500 / 17.05 |
| Tender Fuel Capacity (oil/coal) (gals/tons / Liters/MT) | 15 / 14 | 10 / 9 |
| Minimum weight of rail (calculated) (lb/yd / kg/m) | 75 / 37.50 | 69 / 34.50 |
| Geometry Relating to Tractive Effort | ||
| Driver Diameter (in / mm) | 73 / 1854 | 72 / 1829 |
| Boiler Pressure (psi / kPa) | 200 / 1380 | 200 / 1380 |
| High Pressure Cylinders (dia x stroke) (in / mm) | 19" x 26" / 483x660 | 18" x 26" / 457x660 |
| Tractive Effort (lbs / kg) | 21,858 / 9914.63 | 19,890 / 9021.96 |
| Factor of Adhesion (Weight on Drivers/Tractive Effort) | 4.12 | 4.17 |
| Heating Ability | ||
| Tubes (number - dia) (in / mm) | 132 - 2" / 51 | 251 - 2" / 0 |
| Flues (number - dia) (in / mm) | 19 - 5.375" / 137 | |
| Flue/Tube length (ft / m) | 14.52 / 4.43 | 14.51 |
| Firebox Area (sq ft / m2) | 178 / 16.54 | 182 / 16.91 |
| Grate Area (sq ft / m2) | 41.40 / 3.85 | 42.30 / 3.93 |
| Evaporative Heating Surface (sq ft / m2) | 1557 / 144.65 | 2074 / 192.75 |
| Superheating Surface (sq ft / m2) | 300 / 27.87 | |
| Combined Heating Surface (sq ft / m2) | 1857 / 172.52 | 2074 / 192.75 |
| Evaporative Heating Surface/Cylinder Volume | 182.53 | 270.76 |
| Computations Relating to Power Output (More Information) | ||
| Robert LeMassena's Power Computation | 8280 | 8460 |
| Same as above plus superheater percentage | 9605 | 8460 |
| Same as above but substitute firebox area for grate area | 41,296 | 36,400 |
| Power L1 | 14,683 | 9349 |
| Power MT | 719.34 | 496.65 |