Railroad Forums 

  • market street tunnel

  • Discussion relating to Southeastern Pennsylvania Transportation Authority (Philadelphia Metro Area). Official web site can be found here: www.septa.com. Also including discussion related to the PATCO Speedline rapid transit operated by Delaware River Port Authority. Official web site can be found here: http://www.ridepatco.org/.
Discussion relating to Southeastern Pennsylvania Transportation Authority (Philadelphia Metro Area). Official web site can be found here: www.septa.com. Also including discussion related to the PATCO Speedline rapid transit operated by Delaware River Port Authority. Official web site can be found here: http://www.ridepatco.org/.

Moderator: AlexC

 #1574425  by septaglizzy27
 
am i trippin or is the tunnel under the river cuz i saw that there’s no culvert under the bridge like the broad street bridge on the blvd expressway .
 #1574456  by Return to Reading Company Olney Sta
 
The Market Frankfort line has tunneled under the Schuykill since the early 1950’s. That’s when the subway portion under Market west of the river to the current 46th St portal was constructed. Originally the line’s tunnel portal was just east of the river and it crossed on a bridge (as did the subway surface lines - underground portion of those lines west of river and current portals were constructed at same time.). The line was elevated over Market St from there west.
 #1574457  by NaugyRR
 
They can either bore below the river bed, like how the North River Tunnels between NY & NJ were made, or they can lay tunnels directly on the surface of the river bed, like how the Channel Tunnel between England & France was built.

Both are made of concrete, steel, and iron.

Here's some reading material...
https://www.scienceabc.com/innovation/h ... built.html
 #1574504  by ExCon90
 
According to the linked article, the Channel tunnel (actually two rail tubes with an access tunnel in between) was bored beneath the bottom of the Channel. The North River tunnels are tubes resting on the river bed, although the portions beneath the land surface (and under the Palisades) were bored.
 #1574528  by NaugyRR
 
A little fact dyslexia never hurt anyone, haha; at least I got the methods correct, just mixed up on the geography