Another great example is Metrolink's purchase of low emission Tier 4 diesel locomotives. These have been a disaster in terms of cost & maintenance, leading to service reductions.
If the goal is to reduce emissions, it's better to run more service and get people out of cars.
I envy US transit agencies whose states didnโt require them to buy the first generation of zero-emission buses. The ones they buy later will better.
Sorry, inventors, but I advise transit agency clients never to buy version 1 of anything. The taxpayer is not your beta-tester.