From memory Flyer 1 had to respond within 30 seconds of a call, and Runner 1 within 90 seconds (I could be wrong with the time frames, so feel free to correct me).
Callsign Runner 1 is still in use, and I believe it may still have the 90 second response time. Newcastle had Runner 260 for many years, although that callsign has just been replaced by Pump 260.
And yes they are both pumps... new Scanias I believe.