fixes an overwritten fusion reaction, fixes typo on id computer, makes transit tubes traversible, makes conveyor switches access protected

Signed-off-by: Cael Aislinn <cael_aislinn@yahoo.com.au>

code/game/objects/structures/transit_tubes.dm

@@ -99,6 +99,16 @@ obj/structure/ex_act(severity)
 
 
 
+/obj/structure/transit_tube/Bumped(mob/AM as mob|obj)
+	var/obj/structure/transit_tube/T = locate() in AM.loc
+	if(T)
+		AM << "<span class='warning'>The tube's support pylons block your way.</span>"
+		return ..()
+	else
+		AM.loc = src.loc
+		AM << "<span class='info'>You slip under the tube.</span>"
+
+
 /obj/structure/transit_tube/station/New(loc)
 	..(loc)