Sure, I'll give an explanation.
There are so many street crossings of the railroad between Passaic Street and Temple Ave (6 of them), that there is little need for a pedestrian to try and cross between the street crossings.
The greatest need is at Clay Street, and if a fence cannot be installed, the second choice would be a designated pedestrian crossing, with a gate, such as at Beech Street. Given the choice, I'm sure NJ Transit would fence it. There's a huge "need" for people to cross the tracks there, in order to get from the Carver Park neighborhood to the Park Street area, State Street, or the downtown. Lots of people cross there, and I would guess that more than 50% of the unauthorized pedestrians on the tracks in Hackensack are right there at Clay Street.
It's also very dangerous at Gamewell Place, Myer Street, and Sussex Street, precisely because people WANT to cross the tracks there, to get from one neighborhood to another, or from a neighborhood to the downtown. Wherever there is a street that lines up perpendicular to the railroad, but does not cross the railroad, there will always be people who will want to cross the tracks there. If the street lines up on both sides of the railroad, that's even more likely to encourage pedestrians to want to cross Another example is Stanley Place, but there is nothing to get to on the east side, there's just a few warehouses there. A case could be made for the stretch from Euclid Ave to Main Street, because people might want to cross at Ross Ave. However, for whatever reason, there are simply less people crossing at Ross Ave than Clay Street.
North of Temple Ave there is no neighborhood, it's industry on one side, cemetary on the other. Little need for pedestrian traffic. The same can be said for south of Essex Street. There is no neighborhood on the west side, or any streets that line up to the east side perpendicular to the railroad. For instance, Kansas Street and King Street stop at Green Street, they don't stop at the railroad. And even if they did, there is nowhere to go to, there is no reason for anyone in the First Ward to want to cross the tracks. Who wants to get to the back fence at PSE&G, for instance. There's no incentive.
So if I was pressed to make a case and to set priorities, I would say the greatest need is Essex Street to Berry Street, about 1 mile. Between those two streets there is only two streets that cross the railroad, which are Central Ave and Atlantic Street. I think that would solve 90% of the problem, and it's not a stretch to ask NJ Transit to fund something that would save lives.
Thank you for asking me for the opportunity to explain further.