Transportation Electrification Modifications for Hanson Interlocking

This project consisted of several different contracts to instal a new high-speed interlock along Amtrak’s northeast corridor allowing their commuter trains to switch between Tracks, 3, 2, and 1 at high speed, CSX freight trains to move from Track 1 to Track 2 and makes provisions for the interlock expansion to accommodate an eventual fourth track expansion.

The first contract included installation of 82 new drilled foundations for the new overhead catenary system, which are 48-in. and 42-in. in diameter and 34-ft. deep.  They were drilled with a low head room unconventional drill to install without requiring overhead transmission electrical outages.

Installed steel rebar cages around power lines and constructed three precast retaining walls to construct the new Hanson Interlocking: 41 foundations on the east side of the tracks and 41 on the west side of the tracks.  Constructed a temporary access road to access foundations on the west side of the railroad and installed 28 down guy foundation attachment points for future down guy connections.

Construction was in confined limits, including drilling the shaft, installing the casing liner, setting the steel rebar cages, layout for catenary pole bolts, and placing the concrete for the catenary pole foundations. Kokosing used a large excavator capable of reaching the overhead power lines and a TCC 650 crane to install steel caissons in confined limits for the new foundations and worked in/around Pepco and Amtrak transmission lines during set power outages. To pour concrete for the new foundations on the west side of the railroad, we used a conveyance method (temporary pump hose and pipe) under the tracks as there was no access for a concrete truck. 

The second contract consisted of constructing a one-mile (4,700-ft.) long access road along Track 1 between the WMATA property line and adjacent to the track, with the majority constructed of permeable materials.  Amtrak obtained the permits from Maryland Dept. of the Environment (MDE) and held a separate contract to maintain the site for environmental compliance.  Kokosing obtained a WMATA Real Estate Permit to move a WMATA security fence at Amtrak’s request and coordinated work with WMATA watchmen and inspection staff.

Kokosing surveyed for layout one-mile sheet pile wall, stormwater management facility, and for Amtrak’s catenary poles.  To support the new access road, Kokosing installed over 3,000,000 lbs. of PZ sheets, 13-ft. to 52-ft.  long, 15,000 TN of new aggregate, and a mile of new drainage pipe.  The new road was designed/installed to function as a sand filter for run off. 

Work included rough grading via earth moving equipment to provide a platform for the sheet pile driving.  Installed 5,200 LF sheet piles along the catenary pole line to retain the fill material for the road. Top of finished road is 12-in. below the top of Track 2’s east rail. Kokosing used a Link Belt TCC 750 crane to install the steel sheeting in confined limits and worked in/around Pepco and Amtrak transmission lines during set power outages. Installed 5,000 LF of 12-in. HDPE N-12 underdrain pipe 3-ft. below grade which ran parallel to the railroad 15-ft. to 30-ft. away.

The third contract consisted of installing ¾ of a mile of new electrical duct bank which will supply power to the new interlocking system. The edge of the duct bank is just over 12-ft. away from Track 1.  The new 2 x 4-in. reinforced concrete encased duct bank is 5-ft. deep.  Due to the proximity of the track and Amtrak’s support of excavation specification, crews installed sheet piling along both sides of the duct bank for excavation.  A sliding template and the Movax were used to expedite construction and to keep the required clearances with the overhead catenary and steady span electric lines.