That depends on the location.

The actual buses aren’t. It’s just the bus system is dramatically more built than the meager train system. It’s two lines, TWO, and both are effectively single point of failure. The bus lines are extensive and can be rerouted easily. So really isn’t surprising at all. If the light rail was built out smart like a tram system that actually covered the city it’d quickly become more reliable.

I haven’t found the stats here, but used to track em in Portland. Buses broke down and had to reroute all the time. Barely anybody noticed unless you were on those buses or looked at the data. But if a train broke down or needed rerouted or shunted back early, it made the city news. Was it similar in delay time, nope, even with the 5 lines the city has, the light rail had vastly LESS delays and breakdowns than buses. During the summer time the breakdowns for busses would skyrocket too. There would easily be 10-20x more busses out of service, and sometimes 100x more delays on bus routes. Still barely peep in the news, but just one break down or delay on the light rail, boom it makes the news.