how you know that there was no reason .... were you the loco pilot or signal controller ?
last year i was travelling in bangalore rajdhani and something struct in the loco and it had to stop for around 20 min.there are many factors that come while operating a train which we cannot know here while browsing this site.
That day one reason could be heavy rainfall in gujarat due to which many trains from gujarat going south were diverted through WCR like ahmedabad duronto.
may...
more... be rush was heavy due to that .we dont know.and thats why i said wait for more runs and not come to conclusion on few runs.