I've had a quick look which suggests that Tanzania in the 1940's would be an unlikely place as the couplings had been changed to the East African 'standard type' by that time. Now to find other German Colonial railways - by 1943 Namibia (German South West Africa) had been effectively part of South Africa since about 1918.. Hopefully someone else might have an idea, I doubt Samoa - where there ever any railways there? No sure about New Guinea either...
G
Gavin
Linslade
Bedfordshire
UK
Garratt Locomotives
[
www.beyergarrattlocos.co.uk]