Its relatively rare. They are generally a maintenance nightmare (how do you get new tie in under the existing rails?) plus if the line isn't signalled, determining which way the switch is set could be problematic.
Dave H. Painted side goes up. My website : wnbranch.com
There are some long modern multi-tube tunnels (The Chunnel, for openers) which have special enlarged sections with crossovers so a mishap which blocks one tube won't shut down the entire operation.
I'm aware of one place where the points of a switch were inside a tunnel portal. The frog and closure rails were out in daylight, That interlocking was abandoned when a second bore allowed for double track operation.
Granted that it's under a roof rather than in a drilled tunnel, but the entire puzzle palace at Grand Central Terminal is under Park Avenue and the adjacent buildings.
Chuck (Modeling Central Japan in September, 1964)
dale8chevyss Were turnouts ever placed in a tunnel (like in the Appalachian area) or is this a general railroading no-no?
Were turnouts ever placed in a tunnel (like in the Appalachian area) or is this a general railroading no-no?
CSX's (ex-B&O) Harpers Ferry Tunnel has a turnout in it. The West portal is three tracks wide and the East portal is two tracks wide.
Very rare, however a railroad will do whatever is necessary to facilitate their operations.
On the the other hand subways are real railroads too and most if not all their turnouts are in tunnels.
I tried to sell my two cents worth, but no one would give me a plug nickel for it.
I don't have a leg to stand on.
I imagine someone will come up with some situation somewhere where it happened, but real railroads didn't put turnouts in tunnels. A big factor was that turnouts are often the site of derailments, and you really don't want a train to derail in a tunnel.
Also tunnels as much as possible were single track. It was common for a double track mainline to narrow to a single track to go thru a tunnel. The cost savings of building a single track tunnel often outweighed the bottleneck caused by the tunnel. (To some extent that would be true of bridges too.)
Modeling the N&W freelanced at the height of their steam era in HO.
Daniel G.