Bethesda tunnel west

Cross posted at WashCycle

This post continues the series on the latest plans for the future CCT, as presented by the MTA Purple Line project team to the CCCT on Sept. 13. This post will cover the Bethesda tunnel, west end. The plan view MTA presented for this section is below:

MTA concept for the CCT in the Bethesda tunnel
(click on the image for a large image)
Source: MTA Plan and Profile – Trail, September 2010

A strong feature of the plan is a wide trail that would use much of the width of the tunnel. The MTA project team stated that they will make the trail wider in the tunnel, to compensate for the trail having a reduced clearance to the tunnel ceiling. The trail will be 12′ wide throughout its length elsewhere.

The MTA plans to excavate to lower the tunnel floor so the Purple Line railbed will be several feet lower than the trail is now. Lowering the tunnel floor will create the additional verticle space needed in the tunnel so the trail can be overhead 15′ above the Purple Line tracks and have a minimum 8′ height between the trail deck and the tunnel ceiling. The trail deck will be supported by vertical columns to be built on the tunnel sides. Since the tunnel is at least 32′ wide, there will be room for a very wide trail overhead. As I understood MTA, they had not yet firmed up a decision on how wide the trail will be in the tunnel but they are looking at more than 14′.

This concept of the trail being overhead in the tunnel was briefed to the County Council in Oct. 2008. See the concept sketch from that briefing below. This month’s MTA briefing to the CCCT had the strongest statement I’ve heard from MTA that they are commited to the trail being wide here.

A wider trail than shown in this 2008 concept sketch
can fit through the Bethesda tunnel.
Source: MTA briefing to County Council, Oct. 2008

Trail access to get into the tunnel is a larger problem than is the trail width in the tunnel. Access at the tunnel west end will be provided by two ramps.

The planned configuration of the two trail ramps at the west end of the Bethesda tunnel are shown in the detail from the MTA plan and profile, at right. The switchback ramp that is shown is not new – that concept has been known for several years. That ramp will elevate the trail from Woodmont Plaza to the tunnel overhead. The ramp will be built into the new office building planned for that site, see the April 2009 report on the CCCT website at New Woodmont East II plans go to Planning Board. Only a 28′ wide space is being reserved in the building for the switchback, so there will be less than 14′ for the combined trail width and shy space on each leg of the switchback. Cyclists will be required to dismount to use this ramp because of the relatively narrow width and the tight turns.

There is a second access ramp at the west end of the tunnel, shown in the drawing above going from the trail to Elm Street through the wall at the northwest corner of the tunnel. That access has not been presented in previous plans. It is a much shorter ramp than the switchback ramp, and will give trail users a badly needed alternative.

This wall at the west end of the tunnel can be removed
for direct access to Elm Street.

The Apex Building wall on the north side of the tunnel at the west end is non-structural between the building support columns. The Elm Street sidewalk is on the north side of the wall. The plan is to remove a wall panel and have a ramp go from the trail in the tunnel to Elm Street. The trail on the tunnel overhead and Elm Street are at almost the same elevation, so it would be more like a level bridge than a ramp.

This second access path will go a very long way toward mitigating the congestion problems the switchback ramp would have alone. Many cyclists will find it is faster, easier and safer to use this side access ramp, Elm Street, and the Woodmont Avenue bike lanes than to dismount and walk the long switchback ramp and then to also have pedestrian conflicts while going through the planned Woodmont Plaza corridor. This second access path will also give all trail users easy access to the Elm Street level of the elevators that will be built to serve the Purple Line and the Metro Red Line platforms below. I hope the alignment of this second access ramp will be improved as the preliminary design evolves, to eliminate the sharp turn angle were the ramp meets the trail.

MTA is also looking into having a staircase (not shown on the drawing) to go from the trail down to the Purple Line platform in the tunnel. This would be a good feature, especially for trail pedestrians. Cyclists wishing to board the Metro Red Line would find it much easier to use the side access ramp to Elm Street to use the Metro elevators at the Elm Street level.

Not discussed at the meeting – BIKE PARKING! This new Metro entrance will be easier to reach by bike from every direction except from the north, and the demand for bike parking here will quickly eclipse that at the Bethesda Metro Station. A location for secure bike parking must be found, as near to the Elm Street Metro elevators as possible.

Update – The Sept. 23, 2010 Gazette article Plans unveiled for second Bethesda Metro station entrance has more on the plans for elevators. If the article is correct, there will be two elevators at the Elm Street sidewalk and they will only go to the Purple Line platform, not to the Bethesda Metro Red Line platform. There will be four elevators at the Purple Line platform that will go to the Red Line platform.

Several of the Apex Building wall panels along Elm Street
can be removed to open the tunnel to air and light.

MTA is considering removing several more Apex Building non-structural wall panels along the north side of the tunnel. This would give a more open feeling to the trail and to the Purple Line platforms near the west end of the tunnel.

Purple line opponents have asserted that if a trail is overhead in the tunnel above the Purple Line it would be in a narrow, dark, tomb-like space that would have no escape route if a trail user encountered a crime threat. I suggest they take a hard look at the trail we have in the tunnel now.

The trail we have in the tunnel now.

The trail above the Purple Line would be much wider than is the existing trail, and would have fencing or railings on the sides that give sight lines to the light rail platforms below. Shared tunnel use with transit will generate much more activity and a stronger security presence than in the tunnel now. The Purple Line will likely bring much better tunnel lighting for the light rail station. The west end of the tunnel will be open on the north side to Elm Street. This will compare very favorably with the trail that is in the tunnel now.

The next post of this series will look at how trail access will be provided at the east end of the tunnel.

Tags: ,

2 Responses to “Bethesda tunnel west”

  1. Steve O says:

    Cyclists will not dismount and walk just because there are signs telling them to do so. This switchback will be a conflict problem from day one. Guaranteed.

  2. [...] reported on the plans for the Purple Line and Trail through the west end of the Bethesda tunnel, at Bethesda tunnel, west. Since then the Montgomery County planners at M-NCPPC have released a transitway planning update [...]