Noting that all the remaining NAs, plus G42 and the Climax are in use or being restored at Puffing Billy, are there any other sources of narrow gauge engines, should Puff or the Walhalla GR want another steamer?
In particular noting that there is/was only one steam loco at Walhalla, and that wasn't really strong enough to pull a set on its own (no idea whether this is correct or not, but I have heard that the Henschel could pull about three cars of the weight of the PBR ones, but the Walhalla ones are heavier due to being build from old coal bogies they were donated. But I could imagine that building carriages costs money and they might as well use the materials they got for free - and also if they want to run steam in future they probably want a steamer that can pull more than three cars anyway. Feel free to tell me if I'm way off the mark on this).
Noting that PBR have the South African NGG under restoration, would it be feasible to import another one in future? Google suggests that there are a number of NGGs either privately owned or in parks somewhere in South Africa, how much would it cost to buy one/transport/rebuild/regauge?
Failing that, are there working or restorable geared locos like the Ali-Shan Shay out there anywhere?
Do the 2-foot mountain railways in India (or elsewhere in Asia) possibly have any retired smaller steam locos lying around? Noting that a number of Asian countries run on metre gauge, which depending on the locomotive could maybe be re-gauged to 2'6"?
Assuming that all of those options would be extremely expensive, what are the best guess estimates anyone has only building an NA from scratch? I know that PBR have the dream of one day building 18A - has anyone ever done an estimate on the costs?