Central Line maintenance – Chigwell and Grange Hill
The following information has been reproduced by Epping Forest District Council to facilitate communication and understanding between Transport for London and residents during the programme of construction works to the Central Line between Grange Hill and Chigwell. The information, views and opinions on this webpage are those of Transport for London, and do not necessarily reflect the position or policies of Epping Forest District Council or any other organisation. As such the District Council is not responsible for this content including any discrepancies, errors or omissions.
Background and rationale behind the work
Transport for London (TfL) is carrying out work to stabilise the elevated landscape area known as a rail cutting between Chigwell and Grange Hill stations. This land, which is owned by TfL, spans across 481 metres.
As part of TfL’s programme of inspection and maintenance across the London Underground network, TfL assessed the stability of the railway cutting (the elevated landscape adjacent to the tracks) in this area. This assessment concluded that the cutting fails to meet TfL’s engineering standards and is therefore in need of remedial strengthening work to maintain the safe and continued operation of Tube services on the Central line.
This strengthening work involves a range of construction methods, including discrete bored piles and re-grading of the slope to stabilise the site. These are safety critical works and aim to achieve an asset life-span of 120 years.
The stabilisation work will involve re-grading the earth (to make it less steep), and boring piles into the foundations of the cutting to strengthen the site.
Schedule of work
This work started in September 2018 and is expected to end in winter 2020. The majority of the works will be carried out from 08:00 to 18:00 on Mondays through to Saturdays.
However, due to the complexity of the programme, there will be short periods of time when working outside of these hours is required. This is because this work will require access to the track and will therefore need to take place when London Underground trains are not running. Under these circumstances, TfL will write to residents in advance to provide notice of this temporary change to the schedule.
Temporary site access and security arrangements
The main access to the worksite will be from Hainault Road and Lechmere Avenue/ The Chase to allow contractors and construction vehicles to access the railway cutting. A dropped kerb will be installed at these points to facilitate vehicle access. Temporary hoarding will be placed at the entrance and egress points. The site access point arrangements are temporary and will be made secure once the work is complete.
During working hours, site entrances will be staffed to ensure safe movement of construction vehicles and that only authorised personnel can access the area. Out of working hours, the site will be monitored by CCTV to a remotely located control room which is supported by the British Transport Police.
Road impacts, noise pollution and dirt mitigation
TfL is committed to minimising disruption to residents as much as possible, and will be implementing a range of measures including:
- Working hours – the majority of work will be carried out during the day-time – avoiding anti-social hours
- Road sweepers used daily to remove dirt from local roads
- Acoustic sound barrier used to ‘dampen’ construction noise, where appropriate
- Traffic marshals used at entrances to ensure safe vehicle movement on local roads
- 24-hour remote monitoring system installed on site, manned by control desk linked to BTP and marshals used at access points to ensure only authorised access to the site
- Working with Essex County Council’s Highways team, to introduce traffic calming measures to ensure all vehicles can safely operate on local roads
Working with Essex County Council’s Highways team, a Temporary Traffic Regulation Order (TTRO) has been put in to place for the duration of the project. As part of this, a temporary speed restriction of 20 mph will be in place on a section of Hainault Road, and on The Chase, Lechmere Avenue and Stanwyck Drive. This will apply to all vehicles using these roads, and will help ensure construction vehicles can safely operate in the Chigwell area.
A temporary ‘no parking restriction’ will also be implemented on The Chase for the duration of the work. This will help ensure construction vehicles can safely turn onto The Chase from Hainault Road in order to make deliveries to the worksite. This part of the TTRO will come into effect on 1 April 2018.
There will be a requirement for night-time working, between 22:00 – 06:00 during the programme. This will be necessary when the work being carried out is adjacent to the operational railway and therefore encroaches on the safe operation of London Underground services.
TfL is not yet in a position to advise on when this night time working will take place as this will happen later on in the programme. However, before undertaking the night-time work, TfL will obtain the necessary Section 61 consents, working with the District Council’s Environment team.
This work will be concentrated near the footbridge and the topography of the cutting in addition to the distance from works will shield residents from the noise. TfL will also be carrying out noise monitoring to ensure the levels do not breach standards. TfL will write to residents a minimum of two weeks before the works begins to give advance notice. TfL would also like to give assurances that they will work hard to minimise disruption as much as possible during this period.
Replanting of vegetation
Once the work is complete, TfL will plant the cutting area with grass and a wild flower seed mix. TfL will also plant a number of trees on the top of the cutting. This replanting work will be carried out in line with TfL’s standards for replanting vegetation, which ensures that vegetation is replanted to make the area aesthetic pleasing, whilst also promoting biodiversity.