The calculated distance (air line) between Pyin Oo Lwin and Pyinmana is approximately 160 miles respectively 257 kilometers.
By car or train, the actual journey to Pyinmana is certainly longer, as only the direct route (as the crow flies) between Pyin Oo Lwin and Pyinmana has been calculated here.
Air line (approximately)
257 kilometers
139 nautical miles