The LIRR and MNR, as both separate railroads, have relatively different ways of doing things. While they both share similar equipment to one another, as separate companies if you will, they both have different ways of doing things. One of those many ways involves a practice adopted by railroads known as "schedule padding."
The term "schedule padding " refers to the addition of additional travel time added to railroad schedules beyond what's needed to complete the run with the goal of accounting for potential delays such as congestion, this is done to beef up OTP numbers
While adding a little schedule padding is always a good measure as it allows for trains to recover from minor delays for things such as minor congestion, slow loading, etc, too much schedule padding is exactly the opposite. It
I personally favor endpoint schedule padding. This is because this will allow the train to operate normally and arrive early to it's final destination without waiting around at stations unnecessarily ,
This is what Metro-North does, and while I feel they take it a step too far as for example New Haven Line that terminate at Harrison an average running time of 13 minutes between Mamaroneck and Harrison, while only giving through trains 3 minutes. I definitely feel this is a bit excessive and just looks bad on the schedules, but, at least it won't require the engineer to either one hold in every station, or,
And while endpoint schedule padding isn't great, as it's usually very excessive and leads to unrealistic OTP numbers, it's better than excessive intermediate schedule padding.
The LIRR, on the other hand, generally prefers intermediate schedule padding. This is when they pad the actual running times between each station, and I feel this is generally more intrusive to the actual run. Let's take for example the running time between Westbury and Carle Place. It can easily be done in 2 minutes, however, most of the trains are allotted 3 minutes, and this is done purposely to While I will admit it's not the worst idea to give that extra minute on the Main Line. While that extra minute isn't a terrible thing on the busy Main Line where delays can build up easily, it means that if the train is running on time that chances are the engineer will go at a lower speed between Westbury and Carle Place so they won't have to wait around, and this builds up travel time.
I want to clarify that my point isn't that they should eliminate all intermediate schedule padding rather just look to see whether or not it's really worth it or not. There are definitely examples where intermediate schedule padding is a good thing, and a good example is between Jamaica and Kew Gardens. While in technically the run could be done in 4 minutes, like the LIRR schedules for, rarely can trains actually get there in four minutes,
As far as running times themselves go, thew LIRR definitely tends to be more aggressive and ambitious at times, while Metro-North tends to be more realistic, however the LIRR also tends to throw in little bits of schedule padding here and there into intermediate run times.
I plan to talk further about schedule padding more in the future, and I plan to go in-depth on exactly how the LIRR and MNR calculate there schedule padding in an attempt to look at ways to reduce the fat in both railroads' schedules.