The calculated distance (air line) between San Martín de la Vega and Carabanchel is approximately 15 miles respectively 24 kilometers.
By car or train, the actual journey to Carabanchel is certainly longer, as only the direct route (as the crow flies) between San Martín de la Vega and Carabanchel has been calculated here.
Air line (approximately)
24 kilometers
13 nautical miles