Often I hear trains (usually SEPO)call D3 on the radio that they are "clear of MPX 25 by telemetry." Does the EOT device have GPS that gives the crew the location? Why do they need to inform the dispatcher in this manner, doesn't he get an indication when a train is clear? And it seems they call when they are close to CPF 312 where the rear of the train would seem to be well clear of MPX 25 which is on the far end of the Hill Yard. Thanks in advance for any replies.