On my current playthrough I've just started the Tradecraft quest for the Railroad, but from what I've read it apparently locks out the Plugging a leak quest for the Institute which I'm wondering whether it's true or not.

I am also wondering which quests are the point of no return for all four factions as well as which quests will make a quest from another faction unavailable like the above.

The reason I ask is because I plan on doing as much of the main quest and side quest of the Railroad, Brotherhood and Institute that I can before I am forced to finally choose a side.

Mass Fusion is typically the first main quest that functions as a point of no return. You either complete Mass Fusion and turn the BoS hostile toward you, or inform the Brotherhood before completing Mass Fusion and make the Institute hostile against you. Tactical Thinking for the Brotherhood is the point of no return for the Railroad.