The calculated distance (air line) between Ecatepec de Morelos and Tláhuac is approximately 22 miles respectively 36 kilometers.
By car or train, the actual journey to Tláhuac is certainly longer, as only the direct route (as the crow flies) between Ecatepec de Morelos and Tláhuac has been calculated here.
Air line (approximately)
36 kilometers
19 nautical miles