The date is the date of publication of an article in Scientific American on the Royal Blue express service. This design appears to be a slight enlargement and improvement on the 1883 design. It has taller drivers and slightly higher boiler pressure. Its Wootten firebox probably

Class 139 (Locobase 9762)

Data from Angus Sinclair, Railway and Locomotive Engineering, May 1902, p. 202

This class of James Milholland's 1874 Eight-wheelers were also known as "swallow tails" because the firebox sloped from 46" in the front of the cab to 32" at the fire door with the grate sloping down toward the front. He comments: "This was done to reduce the weight overhanging the back drivers and it gave a very roomy cab." The cab was more of a turret and had a hexagonal plan.

Sinclair also noted that as of 1902, 139 was hauling 3-4 cars on the Allentown-Philadelphia run of 136 miles round-trip and consuming 4 tons coal (59 lb/train mile).

Class 411 (Locobase 3078)

Data from Report of the Proceedings of the 14th Annual Convention of the American Railway Master Mechanics Association - June 14-16, 1881 (Cincinnati: Wilstach, Baldwin & Co, 1881) p. 74.

The report on these early Wootten-boilered engines claimed they would be the largest passenger engines in service at that time. In the May 1881 Journal of the Franklin Institute, J S Bell noted that the height of the firebox was only 2 ft 5 in above the grate.

Over the 59.2 miles between Philadelphia and Bound Brook, NJ, 506 pulled a 15-car, 360-ton train with almost 900 passengers up a ruling grade of just over 1% at an average of 42 mph. In that run, the engine burned 62 lb of fuel per mile, described as the "equivalent to 34 1/2 sq ft per square foot per hour. 411 managed 10 cars in 70 minutes over the same route (50 mph), even though it contended with slow orders on two miles of bridging.

Class D11-s (Locobase 3080)

Firebox heating surface included 42 sq ft of combustion chamber.

These American-arrangement engines were among the last 4-4-0s to be built for a Class 1 railroad. Railway Age (17 April 1914) explained that the anthracite-coal-burning Woooten firebox didn't need to be long, just wide, and it could be carried over the second set of drivers. Also, the Reading didn't need the speed over most of its lines that had led it to adopt high-drivered Atlantics on the Atlantic City run. "The result," said the journal, " is a locomotive which is well adapted to heavy local or express traffic on divisions having moderate gradesand where train loads are within the capacity of an engine of this type."

They carried on until 1941-1945.

Class D3-3 (Locobase 9639)

Data from T. Everett Austin, "Fast Passenger Locomotives," Proceedings of the Engineers' Club of Philadelphia (Vol. V, No. 2, August 1885), pp 97-99.

Notable in this early-Wootten-era camelback were the large number of tubes with a small diameter. A variant with fewer larger-diameter tubes is shown in Locobase 6796.

Class D3-h (Locobase 3077)

Data from Rdg 11 - 1926 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection.

As was the case on many railroads in the anthracite-coal region of Pennsylvania, this Eight-wheeler was a camelback. The arrangement allowed the line to burn the culm resulting from anthracite mining as fuel. The relatively small drivers indicate a mixed-traffic role for this sub-class.

Class D3-h (Locobase 3951)

This locomotive is the subject of a Railroad Gazette essay (22 June 1900) entitled "What is the Ideal Passenger Engine" by SM Prince, Jr., Superintendent of Motive Power and Railway Engineering for the Philadelphia & Reading. The engine was originally built in 1889 and rode on 68 1/2" drivers until Prince took it in hand in 1899 to demonstrate his argument.

"I firmly believe this [a high-drivered Camelback with wide Wootten firebox] to be the ideal type of high-speed passenger engine," declared the Super. What is so fascinating about Prince's assertions is how most of them would be overtaken by history, technology, and especially train demands within months rather than years. Prince, for example, asserted that there was no real value to be gained by adding a trailing truck to a locomotive with two driving axles. "Nothing can be said in favor of the Columbia or Atlantic type," he declared, adding later "Nothing has been accomplished by the Columbia or Atlantic types of engines that can not be more satisfactorily accomplished by the 8-wheel American and 10-wheel types." (Forced to choose between the two, Prince plumps for the 2-4-2 Columbia, further cementing his hold on the adverse trend of history in the face of the consensus that the arrangement rode badly.)

Prince backed up his claims with deeds, building several classes of Camelback 4-4-0s. But the Reading also built several dozen Atlantics, which became known as premium Flyers.

Class D3-p (Locobase 6796)

Data from Rdg 11 - 1926 Locomotive Diagrams supplied in May 2005 by Allen Stanley from his extensive collection.

Like many anthracite roads, this Eight-wheeler was a camelback. It's also likely to date from the mid-1880s, although Locobase cannot confirm the date. The boiler's heating surface area seems very low, but is consistent with the number and length of tubes. A variant with more tubes of smaller diameter (1 1/2") is shown in Locobase 9639.

Class D5-f (Locobase 3079)

Another in a series of camelback Eight-wheelers, this class was one of the most numerous.

Class Gowan & Marx (Locobase 1029)

White (1968) describes differences in cylinder measurements; those given were recollected by designer Joseph Harrison in 1872. One of the first engines to have equalizing levers on the running gear As White shows, there were many ways to equalize the movement of the two axles. That adopted for the Gowan & Marx would appear on thousands of engines and represents perhaps the single greatest American contribution to steam locomotive design (other than sheer size).

Each axle box was free to move within a limited vertical range. The two boxes on each side of the engine were joined by a lever that pivoted around a stand located between them. The stand's vertical movement was buffered by an inverted leaf spring whose ends were secured very near the horns in which the axle boxes rode. As the engine encountered irregularities in the track (a constant occurrence), the movement of each axle box up or down was compensated for by an answering movement in the other box on the same side. Thus, both axle boxes operated as a unit. When combined with the center-pivoting leading bogie, the suspension resembled a three-legged stool.

The Gowan & Marx ran for more than 20 years, 144,000 miles. In one demonstration in February 1840, the engine pulled 101 cars weighing a total of 423 tons (note how small the freight cars of the time were). She burned wood until 1855, when she was converted to burning coal.