I prefer the term linear myself.
Everyone at the table has to accept that they will follow along the adventure, or it falls apart fast.
In my mind there's a difference between linear and railroad. I just got done playing a video game that was quite linear, about my only choice on anything was whether I shot an enemy or tried to sneak past them (usually, sometimes the only solution was to be a murder hobo). It still had fun with the game. Linear gameplay sometimes just happens because of the situation. In a tunnel that's collapsing? If you want to survive you really only have the options of trying to escape the tunnel. A railroad is if the DM tells you that you are going left even if right should be an option, sometimes by using quantum ogres.