So currently the Furgus spur is 10 mph rule 105 track, the proposed pinebush go station sits on the Galt spur. This has some 5mph track on it. The distance between Pinebush GO and Guelph Central is approximately 11.5 miles (18.5 km), which at current speeds would take about 1hr 10 minutes between stations.
With the 15-16 minutes advertised it would be an average speed of 43-46 mph (70-74 km/hr) which would probably mean zone speeds between 50 to 60 mph. (80-97km/hr)
Kitchener to Guelph is 13.9 miles and is scheduled at 22 minutes, (2 minutes less than the 10 mph downtown guelph days) metrolinx padded that schedule so much and I know they can do it in 16 minutes. Cause let's be real 37 mph (60 km/hr) is very generous. VIAs more realistic 20 minutes has an average speed of 42 mph or 70 km/hr). Knowing that info its entirety possible they upgrade to 70 mph (110 km/hr) for the Furgus spur (by then Subdivision)