Maine Central classes C-3 and C-3B
After the C, C-1 and C-2 class Pacifics, the Maine Central ordered the C-3 class machines. Three locomotives were delivered in 1917 and two more C-3Bs in 1924. Compared to their predecessors, they had larger cylinders and lower boiler pressure. To increase the traction they had a booster on the trailing axle. Usually they pulled express trains with ten to twelve cars.
They were rebuilt in 1933 and 1934 and received smaller cylinders which were compensated for by higher boiler pressure. They also received a new boiler, which showed changes especially in the firebox surface. Number 470 still exists today, owned by the New England Steam Corporation, which is having it restored in Ellsworth, Maine. It is scheduled to be completed in 2024.
Technical data
General
| Property | as built | rebuilt |
|---|---|---|
| Built | 1917, 1924 | 1933-1934 |
| Wheel arrangement | 4-6-2 (Pacific) | |
| Gauge | 1,435 mm (Standard gauge) | |
Dimensions and weights
| Property | as built | rebuilt |
|---|---|---|
| Wheelbase | 10.26 m | |
| Total wheelbase | 20.88 m | |
| Service mass | 121.7 t | 127.3 t |
| Adhesion mass | 72.5 t | 80.4 t |
| Total mass | 192.9 t | 213.8 t |
| Rigid wheelbase | 3.96 m | |
| Axle load | 24.2 t | 24.3 t |
| Water capacity | 30,283 l | 34,826 l |
| Fuel capacity | 12.7 t (coal) | 11.8 t (coal) |
Boiler
| Property | as built | rebuilt |
|---|---|---|
| Grate area | 5.249 m² | |
| Firebox surface | 25.363 m² | 28.958 m² |
| Tube heating surface | 250.838 m² | 252.817 m² |
| Evaporative heating surface | 276.201 m² | 281.775 m² |
| Superheater surface | 59.086 m² | |
| Total heating surface | 335.3 m² | 340.9 m² |
Power plant
| Property | as built | rebuilt |
|---|---|---|
| Driver diameter | 1,854 mm | |
| Boiler pressure | 12.8 bar | 13.4 bar |
| Expansion type | simple expansion | |
| Cylinders | two, 635 x 711 mm | two, 610 x 711 mm |
Power
| Property | as built | rebuilt |
|---|---|---|
| Power source | steam | |
| Estimated power | 1,641 kW (2,231 PS) | 1,752 kW (2,382 PS) |
| Starting effort | 167.7 kN | 162.9 kN |
Calculated values
| Property | as built | rebuilt |
|---|---|---|
| Factor of adhesion | 1 : 4.24 | 1 : 4.84 |
| Optimal speed | 60 km/h | 66 km/h |
| Power-to-weight ratio | 13.5 kW/t | 13.8 kW/t |
| Heating Surface Equivalent | 521.2 m² | 544.7 m² |
| Cylinder volume/HSE | 1 : 864.30 | 1 : 762.10 |
| Adhesive weight/Total | 1 : 1.68 | 1 : 1.58 |
| Tractive force/Heating surface | 1 : 10.45 | 1 : 9.98 |
| Grate area/Heating surface | 1 : 63.88 | 1 : 64.94 |
| Firebox/Tube surface | 1 : 9.89 | 1 : 8.73 |
| Total/Superheater | 1 : 4.67 | 1 : 4.77 |
