PART THREE
Livio Dante Porta himself believed at this time that the future for steam should lie in a simple, but super-efficient, design for developing countries capable of burning a wide range of locally sourced fuels such as bagasse, the residue from sugar-cane pulping. In a paper he presented in Buenos Aires in 1963 was a drawing of a two-cylinder compound 0-8-0, which he suggested could be built at modest cost to any gauge.1 Among several points of interest are inside cylinders - in spite of the need for a crank axle - for better lateral balance, with exposed outside valve gear placed ahead of the smokebox for ease of maintenance. A screw mechanism would deliver fuel to a version of his cyclonic Gas Producer Combustion System firebox. Boiler pressure would be 285psi with high-degree superheat. Another particularly interesting feature were twin Franco-Crosti pre-heaters placed under the high-pitched boiler, exhausting through Kylpor blastpipes and chimneys on either side, but not close to the cab.
In stark contrast, the ‘ultimate’ steam locomotives in the UK were a number of National Coal Board ‘Austerity’ 0-6-0 saddle tanks rebuilt in the 1960s and ’70s to include a range of up-to-date features from among those discussed earlier.2 These included some with Giesl ejectors and, most ambitious, some with Porta Ivylpor blaspipes and his GPCS fireboxes, fed by Hunslet under-feed screw mechanisms driven by small steam or diesel engines in the bunker.3 The NCB’s objectives were twofold; a) to suppress smoke emissions in order to meet the requirements of the Clean Air Act and b) to burn coal ‘slack’ with lump sizes averaging only half an inch. The Hunslet under-feed system certainly achieved both and 85 sets were ordered for installation into a range of NCB locomotives from different builders, though not all were actually fitted. Maintenance costs were high, including having to clear out the screw-feed channels to prevent feed-back of burning coal when not working, and few drivers were given sufficient training to get the most from the ‘one-man operation’ potential. However, at Walkden Colliery in Lancashire “the combination of the Giesl ejector and Hunslet underfeed stoker was found to be extremely successful … enabling the haulage of quite prodigious loads while maintaining steam pressure over long periods of sustained hard work”.4 By using a grade of coal that was
