The calculated distance (air line) between Svyetlahorsk and Kastsyukowka is approximately 50 miles respectively 80 kilometers.
By car or train, the actual journey to Kastsyukowka is certainly longer, as only the direct route (as the crow flies) between Svyetlahorsk and Kastsyukowka has been calculated here.
Air line (approximately)
80 kilometers
43 nautical miles