Lourenco Marques 4-6-2 Locomotives in Mozambique

Class 301 (Locobase 14728)

Data from DeGolyer, Vol 63, pp. 93+. Works numbers were 52201-52203 in August 1919, 57397-57398 in October 1923.

Although several South African classes and two Japanese classes were bigger than these Portuguese East African engines, they were nonetheless powerful for their gauge and duty.

Firebox heating surface area included 15 sq ft (1.4 sq m) in three arch tubes. Piston valves measured 8" (203 mm) in diameter. One additional feature doubtless welcomed by the drivers: Ragonnet power reverse.

The specifications for these Pacific flyers spelled out the profile over which they were travel and the coal they were to expect to use. Rolling on relatively heavy 80 lb/yard (40 kg/metre) rail along an 89 km (55.3 mile) stretch, the 301s faced gentle minimum curve radii of 300 metres (984 feet) and grades that at most inclined at 1 1/2% and that for only 1,500 metres (0.93 miles). Transvaal coal had an average calorific power that was 83.3% of the best Welsh coal.

Experience with the first three guided the production of the latter two. For example, the staybolt holes bored into the firebox plates in the first batch were not in the same line and were "slantwise", advises the spec for the second batch. "[W]ith vibration and work of loads of locos, they break too frequently."

Stresses on the locomotive contributed to the failure of driving spring hangers, so 304-305 were to get stronger ones.