With the institute, you'll start to see synth patrols throughout Boston. With the BoS, there are even more BoS patrols than before. If I decide to go railroad, after the main quest will I see railroad patrols?

Would that even make sense? Unlike the minutemen, BoS and Institute, the Railroad do not fight for control over Commonwealth.

That's what I mean. It would seem unlikely that the faction that hides in the shadows would be doing patrols. So what do the railroad do afterwards? Besides the nice perk you get.

Maybe the human Synths now walk around without fearing the Institute and BoS? Nobody says it must be a patrol.

Yeah, I found that the response of the BoS after the main quest line makes playing almost pointless because there are so many patrols you never get to attack anything because the Virtibirds and ground troops are wiping everything out. I thought the Institute was the reason they are there. Now the Institute is gone wouldn't it make sense that they'd go away and leave a small contingent at the airport?

Nope. They actually had two targets: the Institute and the Supermutants. They basically want to destroy anything that could put humanity in danger, which is mostly Supermutants, Enclave and Synths.

Additionally, EC BoS also seems to see themselves as a country (even Maxon tells you to fight for "the country") and now that they established their control over Washington, they want to add Commonwealth to their little empire and further increase their manpower.

All in all, the main force is unlikely to leave until they hear of some new Global Threat to Humanity or the Commonwealth is put fully under their control and purged enough of Synths, Raiders and Supermutants that there is no point in having the Invasion Force there anymore. But until then, they don't really have better things to do.

Yeah well I had to start a new play through before I started shooting down Vertibirds.

I'm not sure if I want to go with the Railroad or Institute with this play through. I wanted to see if you could stick with the Institute and get rid of the Railroad and BoS.

Go with the Institute, you know you want to. I was kind of disappointed I couldn't command Synth armies, get them to defend my settlements etc, but meh.. worth it.

That's an interesting point, I am currently leaning towards a BOS decision, but does their "victory" really have such a big visible effect on the game world and might disturb our ongoing loot, sidequest and explore gameplay? :/

This is awesome and needs to be a thing. Please somebody make it so.

Will you laugh maniacally when commanding your army of murderbots?

Arthur has not entirely swung his chapter of the Brotherhood back to the western ideals there's still a good deal of Lyon in him

Or for when the NCR gets to be too much of a threat to them.

I am pretty sure that EC BoS would rather see WC BoS die than leave their little creation behind... and the more the ratio between BoS-born and Recruits grows, the less will they care about the west. I doubt that they are even at that good terms as WC BoS should not be too happy about EC BoS recruiting (as we have seen in NV, they are VERY stubborn about it).