An Asian Pacific capital city proposes to design, construct and operate a new double track railway from the city to connect to its major airport. Prefeasibility studies that included geotechnical engineering investigations considers that ground conditions are such that the double track railway will need to be constructed both at grade or be elevated on a viaduct as detailed below for the various lengths of line:
0-3km - on grade
3-6km - on viaduct
6-8km - Estuary Viaduct
8-10km - on viaduct
10-15km - on grade
Construction time estimates have been prepared for Stage 1 of the project which will consist of the construction of the viaduct section of the line from 3km to 10km. (An example of a recently completed similar project is on a new high speed railway from Erfurt to Leipzig/Halle in Germany – the ‘Saale-Elster Viaduct which is 6.5km in length – reference below).
Following completion of the viaduct section a separate contract will be let for the installation of the track components where it is proposed to use prefabricated/precast concrete slab track sections (PCSTS) that will be erected in sections for each of the two tracks. For the purpose of analysis, the FFB Slab Track ‘Bogl’ system that has been used successfully in Germany and China will be considered.
It will be necessary to construct PCSTS fabrication plant/s located at a strategic point/s along the length of the viaduct section of the route. Fabrication plant/s of modular construction will take an estimated 3 months to construct and commission and be ready to produce the PCSTS sections. Work on this activity will need to start at contract commencement following a 1-month period of mobilization by the contractor.
Each modular plant should be capable of producing an estimated 75 off, PCSTS sections per day of operation. The PCSTS sections are to be stockpiled at the fabrication plant after manufacture for 2 months prior to the track laying operation on the viaduct commencing.
Sections of 60kg/m rail will arrive at the start of the viaduct section (3km point) on special flat wagon trains, to complete the track laying operation, and once installed will need to be site welded to ensure that there is continuous welded rail installed over the whole length of the route. It is assumed that on grade sections of line will have been completed and track laid. On each side of the proposed viaduct route it will be possible to construct vehicular access tracks except for the estuary section that will be over water i.e. no roads can be built. 3
b1. Prepare a step-by-step, detailed methodology for how you would propose to construct the double line of track work for the length of the viaduct. Include a list of construction plant and equipment that will be needed for the operation.
b2. Prepare a construction schedule for the track installation contract on the viaduct (commencing at the 3km point) in Time-Chainage Diagram (TCD) format using XL or AutoCAD or other graphical means showing all activities that need to undertaken for the construction of the double line track including site establishment, and equipment set up. Include all assumptions and calculations for estimating construction duration.
b3. Prepare a second TCD, assuming that construction activity is undertaken from the 3km and the 10km simultaneously. Include all assumptions and calculations for estimating construction durations.
b4. Prepare a Safe Work Method Statement (SWMS) or JSA for the lifting equipment that would be used on the viaduct including working at height.