All forms of “rapid” transit involve occasional breakdowns. But In contrast to Suspension Monorail, breakdowns of the ground-based options bring the rapid transit system to a standstill, while disrupting alternative forms of transport.

Recent examples: -
Sydney Light Rail breakdowns, 12 Nov 2019, and
21 Jan 2020  [passengers trapped for 70 minutes]

Sydney’s “Vague and half-baked” lagging CBD ‘Light Rail’, December 2019...

"At this point it’s more likely that this project has fundamental design flaws," said Opposition transport spokesman Chris Minns. [such as being ground-based, sharing speed limits and problems inherent in that mode?]

The 2012 State Infrastructure Strategy: First Things First report said that, while there was merit in investigating the viability  of a line between Central and Randwick, it warned any potential service  through the CBD could face "significant costs and delays". "Light rail is however, significantly more expensive than bus services,  has no material speed benefits, is less flexible in traffic and if service reforms to the operation of CBD bus services are implemented,  does not offer significantly greater capacity," the report said.
[Sydney Morning Herald, 20 Jan 2020]

Is Sydney unusual? NO - This, from Melbourne:

“ ...The figures also show some tram services in the CBD have been delayed for up to two hours due to traffic jams and collisions. Yarra Trams said the delays and low speeds were mainly due to the "unique nature" of the tram network. About 75 per cent of the tram network operates on shared roads with other  vehicles, meaning trams are often vulnerable to traffic accidents on the road....

 Yarra Trams spokesman Simon Murphy said the challenges facing the network would only get worse in the years ahead. "Melbourne's tram network is unique, 75 per cent of the network is actually shared  with other traffic on Melbourne's roads and that really presents  challenges in terms of congestion, particularly as Melbourne grows, and  that's going to continue to be a challenge as we go into the future," he said. ”

www.abc.net.au/news/2017-05-19/melbourne-trams-among-slowest-in-the-world/8541228

Crash causes tram to derail in Vic, 5 Oct 2019. 7 injured, 1 seriously,  car driver cut from wreckage, traffic jams 2 hours, trams disrupted due to power issues. Derailment is common - 15 to 20 yearly, and it takes hours to fix: Why do trams derail?