0-4-4 "Forney" Steam Locomotives in the USA

Class C L Flint (Locobase 16502)

Data from "Locomotives as the Exhibition-Table of Leading Particulars", , Scientific American Supplement, No. 35, (26 August 1876), pp. 548-549; and "Double-Truck Locomotive by the Mason Machine Works", Railroad Gazette, Volume IX [9], No 20 (18 May 1877), pp. 221-223. (Thanks to Chris Hohl for his 1 February 2025 email correcting the Whyte wheel arrangement.) Works number was 571 in 1876.

William Mason was already known as an innovative designer of locomotives and several of his Mason-Fairlies had entered service. Fairlie's grouping of coupled axles in a swivelling truck allowed locomotives to negotiate very tight curves, a useful quality in narrow gauge operation. A key element was the provision of swing links to keep the cylinders horizontally indexed to the boiler as they traversed.

Fairlie's patent included the use of the bogie's hollow central pivot. Live steam from the boiler traveled in a dry pipe to the smoke box at which the pipe curved back under the boiler to a junction with a pipe that led down through the pivot to a divided pipe. On each side of that two-ended pipe a branch pipe conveyed the steam to the front and into the cylinder's valve chest. But maintaining tight connections along such a circuitous route while the cylinders traversed back and forth usually proved more trouble than the ability to take sharp curves seemed to warrant.

Mason's adoption of Egide Walschaert's constant-lead radial valve gear set him apart as virtually every other North American locomotive of the time used the Stephenson (aka Williams-Howe) link motion inside the frame. Even that feature was compromised by the traversing truck in that the reversing rod, which led from the cab, had to be connected to the valve stem through a linkage. (The more Locobase describes this, the more the setup seems vastly too complicated to function properly.)

The engine premiered in 1876 at the Philadelphia International Exhibition (often called the Centennial Exhibition). After its time there, it was sold to the NY&MB as the C L Flint. It was the first of several Mason Bogies, but the only one with 11" cylinders. When the Long Island Railroad purchased the short line in 1885, the new owner widened the C L Flint's gauge to the standard 4 ft 8 1/2 in (1,435 mm) and renumbered it 103.