Removing the time of the train ride from the journey shows that his trip to get on the train took him 8 hours – 6 hours = <<8-6=2>>2 hours.
Converting this time into minutes shows that getting to the train took 2 hours * 60 minutes/hour = <<2*60=120>>120 minutes.
Waiting for the train to arrive took twice as long as his walk, so 15 minutes * 2 = <<15*2=30>>30 minutes.
This means that his bus ride must have taken 120 minutes – 30 minutes - 15 minutes = <<120-30-15=75>>75 minutes.
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