By Pepper Parr
BURLINGTON, ON October 5, 2012 Here is what the rail crossing on King Road looks like before the work to put in a grade separation began:
The plan was to take out the four rail lines, build a supporting wall and install a diversionary rail track that would handle freight during the three and a half days of round he clock construction. It was a mammoth task that would be done by CN Rail’s contractors with the city as part of the team.
These are the stages the construction project will go through.
This graphic shows where the supporting walls were going to go. They are in blue; one on either side of the trench that was to be excavated and another where the diversionary railway line was to go. The green line is a creek that had to be diverted during the construction phase.
The first stage was to build all the supporting walls and then to excavate a large trench using an open cut approach.
In this schematic the diversionary track is shown between the blue line and the green line, which is the creek that gets diverted. The green boxes indicated where the “box” that will become the tunnel under the railway tracks is also shown. The box is a single hunk of concrete that weighs over 5 million pounds.
The passageway or tunnel that was to be created is a box that was built before hand and laced in a position where it could be shoved into position once all the excavation was done.
In this photograph a freight train is using the diversionary track put in place. That track is supported by a wall that was built to hold the track up while long freight trains cross. That support wall will be punched through once the concrete tunnel box is in place. The stretch of King Road that will disappear when the underpass is built can be seen on the extreme right.
All the earth from the green box up to the blue line has to be excavated and taken off the site.
This schematic shows the rail lines out and the concrete box that will become the tunnel traffic will drive through when the underpass is complete ready to be pushed into place.
The next step is to remove the four railway lines that currently carry freight and commuter traffic. These lines come out on the Friday evening at 9:00 pm and excavation begins.
In this schematic the railway tracks are back in place, the tunnel is in position and the diversionary rail line has been taken out.
When the tunnel has been inched into the excavated space it is back filled in with gravel and the four rail lines that were removed are put back in place. All that has to be done by 5:00 am of the Tuesday, October 9th.
An aqueduct will be built to carry the creek over the tunnel.
Traffic can’t use the tunnel yet but commuter trains and freight can resume normal schedules. The final step is for the creek that was diverted to be brought back. It will now flow over the tunell that carried traffic north on King Road. This represented a challenge until they decided to build an aqueduct that will carry the water over the tunnel.
This is an aerial view of the work being done at 4:30 pm Saturday afternoon. The black topped shape to the left of the yellow crane is the tunnel that will be pushed into place with hydraulic jack hammers. You can see the orange back hoes in the space that is being excavated.
The work started promptly at 9:00 pm Friday and by midnight Saturday most of the excavation work was done.
This is a view of trucks coming out of the tunnel loaded with earth that has been excavated. A truck got loaded with earth in just under two minutes. The jack hammers that will nudge this tunnel into place can be seen in the lower left. Identical jack hammers are in place on the right hand side. The King Road that used to cross over the tracks is on the right.
Giant truck back into the tunnel that wil get pushed into position when all the excavation is completed sometime between 2:00 am and 5:00 am on Sunday the 7th of October.
