The Port Jefferson LIRR is one of the few lines left if not the only line that relies on diesel locomotives to operate. There are a lot of reasons why the line can't be electrified, which means service is very slow and pretty cumbersome.
Here's the Port Jefferson train arriving at Hicksville station to pick us up to take us off the electrified rails to Port Jeff. Once I arrive there, it's still a 20 minute drive out to where I live.
I think within the next few years we will move closer to NYC but until then this is one of the lifelines I depend on to get to and from the city. Luckily I just drive to my work in Queens, but for some people this train is an everyday necessity.