How to tell where a train originates? Train number?

Hi,
I'm wondering if there's an easy way to tell where a train originates, especially on the NEC. I often start at NY Penn but many NEC trains originate in Boston before heading south. Is there an easy way to tell where a train starts? Does the train number offer that info? For example, train 133 starts at NYP but train 93 may start at BOS.

I want to find trains that start at NYP so I don't have to worry about delays with an inbound train from another city before heading south to WAS. For today it turns out I picked the right train.

Thanks,
-RM