It was WWII.... so likely they wouldn't have been able to purchase locomotives from the US, Britain or Germany. Their shops would have been capable to do the work, so buying used narrow gauge locomotives (for their narrow gauge) then choosing one to convert to standard gauge made sense... likely they didn't have options.
Randy
Randy Hees
Director, Nevada State Railroad Museum, Boulder City, retired
PacificNG.org - a curated Wiki on Pacific Slope Narrow Gauge www.pacificng.com
Moderator - Railway Preservation News www.rypn.org