The MTA briefed its new plans for the Purple Line in the Lyttonsville area at a March 14 neighborhood meeting. The Gazette summarized the plans at Residents pleased with revised Lyttonsville Purple Line plans. I think trail users can be pleased with the plans, but with one important issue that bears watching closely as the design is refined – that is the proposed trail underpass near the Grubb Road/Terrace Drive access path.
The MTA has made the March 14 presentation materials available on its website at work sessions – Lyttonsville Area. The presentation includes this map of the new CCT alignment:
(click on the map for a larger view)
(source: MTA work sessions – Lyttonsville Area)
A larger areal map of the proposed new arrangement is at Map of Refined Lyttonsville Alignment. It shows details much better than the map above.
Overall I like the new proposed trail alignment better than the previous one that I had reported on here last fall. This new plan returns the trail to the neighborhood (south) side of the Purple Line project, for easier access to the trail from the neighborhood. This trail access is most improved in the area of Kansas Avenue and of Talbot Avenue at the east end of the Lyttonsville neighborhood, where the prior plan had the trail cut off from the neighborhood by the Purple Line tracks.
The new plan does have some drawbacks, however. One is that it will have the trail cross Stewart Avenue at-grade. While traffic there will be light and safety can be managed, it is nonetheless a loss from the previous plan that would have realigned Stewart Avenue there and would have given a grade-separated trail crossing.
(source: MTA Map of Refined Lyttonsville Alignment)
But the biggest concern I have with the new plan is at the western end of this area study – near the Grubb Road/Terrace Drive access path. The new plan proposes to keep the trail on the north side of the Purple Line from the west, then cross under the Purple Line tracks to the south side in an underpass just to the west of the Grubb Road/Terrace Road access path. MTA asserted at the March 14 meeting that their studies were showing the previous plan, to bring the trail under the Purple Line at the Rock Creek bridges, was proving to be creating too much difficulty and expense for the bridge designs. MTA has decided it will be easier to keep the trail on the north side of the Purple Line across Rock Creek and Rock Creek Park and to make the crossing with an underpass at this new point farther to the east.
I think MTA will be forced to reconsider this new plan for a trail underpass, because the existing terrain in this area will not support an underpass. The Purple Line will need to stay low as it climbs up from its Rock Creek bridge. The old B&O railbed (and the existing Interim Trail) are in a cut at the Grubb Road access for this reason. The Purple Line will not likely be elevated much higher than the existing old railbed is here, because that would force the Purple Line to climb too steeply from the Rock Creek crossing. But the trail cannot easily stay at an elevation that is even lower than the Purple Line, to cross in an underpass here, without being in a very deep cut, or in a long tunnel. Either will be very undesirable.
We need to watch this proposed trail crossing very closely as it evolves. I think as MTA gets into the design process, MTA will find that it needs another location, likely to the west, where the trail crossing will not have to go to war with the existing terrain.