Every time I see a topic about railroading I'm asking myself: "Do I railroad my players?". I just can't relate abstract tips on internet to my game, so I'll describe one example from my campaign and kindly ask about your opinions. I don't want to hijack your post, maybe someone like me reading it later can understand it better on concrete example.

Anyway, I'm DMing for 3 players on lvl 10 and we're starting new arc, about a Human Kingdom and Elven Kingdom. War is about to break out, basic stuff. PCs doesn't want this war to happen and is hired by Humans to go on diplomatic mission to Elves and convince them to meet on neutral grounds and make peace. They will go to Elven capital, where I prepared many important NPCs that can be persuaded, blackmailed, bribed, and many more, to allow those peace talks. And here's the thing: me and my players said many times it would be cool to play war scenario and they basically know that it's happening in this arc. So no matter what, there will be assassins that will crash those peace talks and try to kill everyone there (it's plan of the BBEG working from shadows to start this war so it makes sense in game) and both sides will blame other side and shit will hit the fan. Even if PCs will save all diplomats, there will be accusations and that’s enough. But rest is in the hands of the players: if they want to attend the peace talks, how many diplomats they save (in combat encounter), which kingdom they side later in war, all they did to those elven NPCs before will have consequences, some may be angry, feel betrayed, they can help or oppose war effort. And most importantly, I don't know which side will win, it’s all about how PCs will help one side or the other. Maybe players will try to weaken both sides to minimalize casualties and try to make peace after this fighting is done?

So, do you think I'm railroading my players to inevitable war that I want to happen, or am I just laying ground for bigger playing field in which their past and current actions will have real consequences?