There's no need to. The Walpole Jct. northbound wye switch for freights is barely 1500 ft. south of tunnel, which itself is less than 200 ft. long. Diverging traffic is sorting itself in this span, so a gauntlet is 2 interlockings too many for such a very short stretch and would serve nothing but to slow everything down. No traffic whatsoever will ever be inconvenienced by such an incredibly short length of single.I'm not sure of the dimensions but if Passenger equipment could clear that tunnel with two tracks you could build a gauntlet track through it to give freight trains clearance.
It's historic...oldest RR tunnel in Massachusetts, dating to original 1848 Norfolk County RR construction and last modified after the Civil War. Probably the second-oldest surviving in-use RR structure in the state period after Canton Viaduct. No way are you touching that, and (as ^above^) there's zero reason to. As long as the freights stay centered under the arch this one is probably also OK as-is for electrification, too.Is that an old '60's GP38?
Widen that bleeping bridge/tunnel relic. Jesus Christ/