Balancing a 4-4-0

[Mayner]

Designing/building a 4-4-0 to run reliably and haul a decent load is a significant challenge to both manufacturers and modelers alike.

 Mike Sharman developed the "free bogie" weighted tender principal for modelling Victorian single driver locos on his 19th Century mixed gauge layout the basic idea is not unlike the Engerth principal which was developed in Austria during the 19th Century https://en.wikipedia.org/wiki/Engerth_locomotive.

Designing the GSR 52 Class to haul a decent load was a significant challenge as there is very little space in the firebox above or below the motor to add weight.

98 weighted and balanced with all 4 driving wheels on the track.

Trailing driving wheels not quite in contact with the rails.

Underside of loco and tender. Centre and leading tender axles free to float up and down in slots, rear axle running in fixed bearing. Tender drawbar adjusted to transfer weight from tender to loco. The bogie is not load bearing but could be fitted with simple springing.

 

Tender and drawbar. 

Boiler weight. Cerrobend or Woods Metal weight and modelling clay plug to secure in place. 

Woods Metal melts at approx. 70°  I sometimes pour the molten metal into the boiler to fill the area behind the front tube plate but used an existing cast weight and clay in this case.

Loco and tender weights. The weights were originally cast for the MGWR 2-4-0, but sheet lead or self adhesive tyre weights would also do the job.

In this case 98 comfortably hauled 12 IRM 4w wagons or 3 MM Cravens. I wasn't able to test 98 with more than 3 coaches, adding 1-2 additional coaches tended to derail the entire rake

 

[GSR 800]

She's a thing of beauty John, even more so underway.

[David Holman]

Only just noticed this thread, so must pay more attention, as would have been useful with my mail train 4-4-0!

 Having seen numerous mentions of balancing such locos via weight on the tender draw bar, it was really interesting to see it properly explained, so many thanks John. Was starting to think I may have to go down this route with Wolf Dog, but the small size of the ABC motor/gearbox has enabled a fair bit of lead to be packed around it in the ash pan. Add in a couple of inches of 18mm solid brass road in the boiler and some more lead in the firebox and it was at last able to move the three coaches. Whitemetal crew help too!

 Have included my lineup often of the century locos on the fiddle yard table.