The calculated distance (air line) between Trongsa and Samdrup Jongkhar is approximately 78 miles respectively 126 kilometers.
By car or train, the actual journey to Samdrup Jongkhar is certainly longer, as only the direct route (as the crow flies) between Trongsa and Samdrup Jongkhar has been calculated here.
Air line (approximately)
126 kilometers
68 nautical miles