Would it be possible to build a High-Speed Rail on narrow gauge by making it electric (low centre of mass due to battery weight = higher stability) and reducing the friction on the wheels (lubricant?)? Would this help countries Africa integrate all of their territories better (integration = political stability = economic development) at a low cost, so as to not drown them in debt? Also, I realise that for the battery to increase stability in every cabin, each cabin would have to be able to drive independently. (maybe spftware engineering can help make all the train cars start at the same time?)
No need to lubricate the wheels, the rolling resistance of a steel wheel on a steel rail is already very low; the main forces at work are the gradients, inefficiencies the traction system (motor, gears etc.) and air resistance.
Non-standard track gauges mean a reduced carrying capacity, and greater cost of rolling stock, as you no longer have the economies of scale, and access to a vast second-hand market for engines, carriages etc.
As for the stability, the ability of a standard-gauge train to remain on the rails, despite wobbly track, and elderly rolling stock, is quite remarkable; if you were in the UK, I'd refer you to the 1938-vintage trains on the Isle of Wight, which until recently gave a hair-raising ride without coming off the rails, but there will probably be plenty of examples in your country.