The calculated distance (air line) between Samdrup Jongkhar and Tsirang is approximately 87 miles respectively 139 kilometers.
By car or train, the actual journey to Tsirang is certainly longer, as only the direct route (as the crow flies) between Samdrup Jongkhar and Tsirang has been calculated here.
Air line (approximately)
139 kilometers
75 nautical miles