Which cars are you referring to?? The new haven line M8's are some of the newest rail cars in the country, if not the newest.
I know there are some M2 sets still sometimes used but those will be replaced once the 30-60 some odd bar car sets come in.
Also on a separate note, you really can't fault the MTA here for running old cars, they actually do some pretty good maintenance on there fleets both commuter and subway. Running old cars is about maximizing the invest in your fleet, the average lifetime generally being around 40 years.
It seems the MTA learnt there lesson with differed maintanance after the 80's. Just look at the current state of MBTA to the north or WAMTA to the south (it also helps the MTA has a large dedicated funding stream which allot of other transit properties in US lack)
they have M8s but on certain lines they still run those old ones that are over 40 years. Back in 2013 40% of the fleet was out of service due to extremely cold weather
Nothing really wrong with old trains tbh assuming they are maintained and refurbished.
The intercity 125 in the UK despite being over 40 years old is still fast (125mph), reliable (engines have all been replaced fairly recently) and very comfortable and quiet, even in standard class.
And in my experience, the 125 is much nicer than the newer Pendolino, which is claustrophobic, dimly lit, and the areas around the toilets smell of piss.
If you want to see a case study in exactly what you're talking about, you could check out the Australian version of the same train, the XPT, which is in dire need of refurbishment.
