This model generally requires a 26″ minimum radius for satisfactory operation.
A view of the dismantled drive arrangements. Also visible is the rear truck pivot arrangement which on this engine is currently not centred on the truck. Note this particular model has no engineered arrangements for sideways displacement of the rear truck, however it does run around Precision Scale flex track accurately curved to 48″ radius without problems.
A small number of kits were produced at the end of the main build program.
Brief prototype locomotive notes
The prototype locomotive was built by Hinkley in 1877 as their works #1251 for the Billerica & Bedford Railroad “Ariel” as a strict cab forward Forney design, and also served as;-
Sandy River #1 Dawn (1879 – 1890) rebuilt as a conventional boiler first locomotive.
Rebuilt in 1882 with longer wheelbase, larger cab and water tank.
Sandy River & Rangeley Lakes #1 (1908 – 1912).
For more information about the prototype locomotive, click here.
Putnam & Stowe model locomotive #1 curvature, grade and haulage capability tests performed by Ed Kozlowsky.
Ed performed these tests to evaluate the capabilities of small On2 engines that he had acquired in order to determine whether any of the original HO bench work then in use could be salvaged for use in On2, in particular a 24″ radius helix with a 2.7% rise. Ed’s existing bench work and space constraints meant that the conventional published “wisdom” of “needing at least 36″ radius because of the stiff Forney’s needed a reality check.
The test subject was a Putnam & Stowe Sandy River #1. Ed balanced the engine so that both drivers were loaded as equally as possible by adjusting the spring over the rear truck. Before this, one driver definitely had more weight on it than the other. Note that there is a slot in the truck bolster allowing the truck to swing sideways.
1. Laid out a 24″ radius curve on a level table using Precision Scale Company code 70 flex. The Forney had no problem in either direction.
2. Added one 24′ and one 28′ box car. No problem in either direction in the curve or transitioning with no easement.
3. Using double sided tape, I placed 3 sections of flex track on the helix starting from straight with no easement to full 24″ curve. No joints were soldered, so some kinking at the joints was inevitable. Forney ran without mishap upgrade boiler first and tender first.
4. I added the 28′ car next to the engine and the 24′ car after. Boiler first there was no derailment or problems.
5. I then switched the order of the cars without mishap.
6. Here is where I expected if there was going to be a problem it would show up, tender first pushing the cars upgrade. My thought was that the wide swing of the coupler would push the engine sideways enough to derail her. Surely she would catch on one of the imperfections of the rail joints and derail. I watched closely as the little Forney negotiated the helix without so much as a hint of trouble. I did it over and over again on different days with different cars all with the same results.
7. I’ve experimented with #5 turnouts with the same results.
8. Trying different combinations of cars, the most I could haul up the grade was 2 box cars and 3 flats. I wasn’t really happy with that.
I have nothing but these little engines (Putnam & Stowe Forney’s), so I don’t know how larger ones would perform, but I don’t plan on running anything larger anyway. Also, I have no interest in running long passenger cars. For the operation I am planning, a short car or caboose fitted with seats will suffice. If I do want to run something longer in the future, I’ll buy one and figure out how to make it work. It’s impossible to be a model railroader without making compromises.
Ed Kozlowsky, Sanford, Maine.