The calculated distance (air line) between Gremyachinsk and Yekaterinburg is approximately 156 miles respectively 251 kilometers.
By car or train, the actual journey to Yekaterinburg is certainly longer, as only the direct route (as the crow flies) between Gremyachinsk and Yekaterinburg has been calculated here.
Air line (approximately)
251 kilometers
135 nautical miles