TfL Ref: FOI-1719-2122
Thank you for your request received by us on 4 November 2021 asking for information about noise and trains on the Northern Line.
Your request has been considered in accordance with the requirements of the Environmental Information Regulations and our information access policy. I can confirm that we hold some of the information you require. You asked:
1. How many of the Pandrol Vanguard rail fastenings, if any, have been removed from the Northern Line?
Some Pandrol Vanguards (PVs) track fastenings were removed for a short time when we were required to carry out maintenance work on the rails and other components. They were placed back once the maintenance works were completed. They haven’t been removed permanently.
- Was there any consultation with the unions before Pandrol Vanguard was installed by LU?
No, there was no consultation with the unions regarding the fitment of PV, as it was installed to address residential noise complaints ahead of the launch of Night Tube and no impact was anticipated for colleagues.
- What testing, if any, was done by London Underground on Pandrol Vanguard before it was rolled out across the network?
PV was first installed on the Central line in the Holland Park area and it performed well. The testing that was carried out was to ensure the introduction of PV would not cause any safety concern in terms of running trains over it. In addition to this, measurements were taken to understand the impact this would have on residential noise, which was raised as a concern for Night Tube.
- Dates and Locations of where Pandrol Vanguard was installed on the Northern Line?
| Start |
Finish |
Date of install |
| South Wimbledon |
Morden |
03/07/2017 |
| Camden Town |
Euston |
03/07/2017 |
| Camden Town |
Euston |
12/05/2017 |
| Camden Town |
Euston |
Completed in two phases:
|
| Kentish Town |
Tufnell Park |
01/06/2017 |
| Euston |
Camden Town |
28/03/2018 |
| Euston |
Camden Town |
Completed in two phases:
|
| Camden Town |
Kentish Town |
20/06/2018 |
| Kentish Town |
Camden Town |
20/08/2018 |
| South Wimbledon |
Colliers Wood |
19/10/2018 |
5. What are the decibel readings before and after Pandrol Vanguard was installed on the Northern Line?
Noise levels from the train operator’s cab for the Northern line are listed below:
2018 average of 75.9dB*
2019 average of 75.6dB
2020 average of 79.7dB
*Around 60% (1240 metres) of the Northern line PV was installed after the 2018 noise survey took place. There are a number of factors which impact these noise levels, including the overall condition of the track.
- Who decided that Pandrol Vanguard should be rolled out across LU?
The London Underground Engineering team, in agreement with the LU Head of Track.
- When London Underground first became aware that Pandrol Vanguard had been a failure and in fact made the excessive noise even worse, why wasn’t it removed straight away?
PV had been installed to address groundborne noise which was impacting residential properties. The installation of PV has proven successful at addressing residential noise in the majority of locations, which was shown during property noise measurements taken before and after PV had been installed. The average improvement in the properties was circa 9dB and resulted in many noise complaints being rectified.
Due to the success of PV in terms of mitigating residential noise, we are not able to remove it without considering the views of residents who may be affected by noise, and potential enforcement from Environmental Health Officers. It is recognised that there is an impact on train operators and passengers and whilst we are within an acceptable level of Health Safety & Environment guidance in the PV locations, we are taking action to address these concerns. As a result, any changes made to remove PV would need to be done in a balanced way, ensuring we reduce the in tunnel noise whilst not adversely impacting the residential noise.
- How many Cab Door Seals have been replaced on the 95 Stock following Reports of faulty cab door seals in Train/Car Defect Logbooks?
14 cab door seals have been replaced on the Northern line fleet from 1 May 2017 up until 12 November 2021.
9. Could you please provide the Noise recording reports for the entire Northern Line from the years 2016, 2017, 2020 and 2021?
We do not hold data for 2016, 2017 or 2021, we only have data for 2018,2019 & 2020 which is attached. Whilst there is no legal obligation to carry out annual noise exposure measurements, London Underground has endeavoured to carry out annual measurements, however due to operational requirements and restrictions brought about by the pandemic, we were unable to conduct measurements in 2021. We plan to resume these in 2022.
A full baseline survey of the Northern line was last conducted in November 2020; this assessment against the Regulations remains valid.
10. What measures if any, have been introduced by London Underground to prevent Decompression incidents from occurring when entering the southbound tunnel between Colindale and Hendon Central which has been regularly reported by drivers?
There is no regulatory framework setting any standards relating to this. Decompression illness occurs in very specific environments such as those encountered in deep sea divers, and is not applicable to the work environments in question. Pressure changes of the type encountered on transport networks (those referred to here) are not thought to represent a substantial risk to health. We would be happy to examine any reports or data which indicate this could represent a significant medical hazard in this environment.
11. There is a reoccurring problem at London Underground Occupation Health with drivers complaining of hearing problems such as Tinnitus and NIHL, specifically in their left ear. Drivers also report of their hearing have deteriorated in there left ear during Age related medical appointments. What action, if any, have London Underground taken to address this issue?
We carried out an audit relating to train operators’ hearing in 2018 with no evidence of noise induced hearing loss. There is advice for managers on the Safety Health & Environment management system with regard to health surveillance, risk assessment and identifying who requires noise health surveillance. TfL Occupational Health is set up to provide noise health surveillance if needed.
At present, train operators are not exposed to a level above the action value requiring hearing protection (as set out in the Control of Noise at Work Regulations). However we offer our staff a variety of ear defenders to make them feel more comfortable while operating trains on the Tube network. We will continue to discuss this issue with our unions to make sure that we address any concerns raised by our staff.
12. How does London Underground calculate the average noise for the Northern Line?
Noise is measured on the average exposure over an 8 hour weighed period as per the Health and Safety Executive’s regulations. This measures the whole shift’s exposure, which includes breaks, driving time and changing driving cabs (all duties of a train operator).
Noise levels are measured in the driver’s cab during normal operating conditions. The measured values are the Equivalent Continuous Sound Pressure Level (LAeq) and the Peak Sound Pressure Level (LCpeak); these values are determined for multiple runs between terminal stations. The LAeq and the exposure duration (based on the Temporary Working Timetable) is used to calculate driver noise exposure in terms of the Personal Noise Exposure Level. For the assessment of drivers exposure to noise on the Northern line, we have used either the logarithmic mean or the highest LAeq values obtained during repeat measures to calculate the Personal Noise Exposure Level. This value and the LCpeak is used to assess against action and limit values defined in the Control of Noise at Work Regulations 2005.
13. Why are Ear Defenders not mandatory for drivers on the Northern Line when noise levels recorded by LU, are above 120dBs?
London Underground follows regulatory procedures, and ear defenders only become mandatory by law when the average noise exposure over time weighted average for an 8 hour shift is 85dB or over. The average noise currently recorded on the Northern line for some shifts is between 79dB and 81dB. When the average noise exposure is between 80dB and 85dB, the provision of ear defenders is made available, but not mandatory to wear. The 120dB referred to here is for peak noise exposure which is only for a short period of time, and peak noise limit is 140dB.
The Control of Noise at Work Regulations 2005 require the mandatory use of hearing protection when noise exposure is at or above the Upper Exposure Action Value. This value is equivalent to a Personal Noise Exposure Level of 85 dB(A) normalised to a daily 8-hour period or a weekly 40-hour period and a Peak Sound Pressure Level of 137 dB(C). Hearing protection is available but not mandatory for drivers on the Northern line as noise exposure has been assessed to be below a Personal Noise Exposure Level of 85 dB(A); the LCpeak is below 130 dB(C).
Please refer to Regulation 4 of the Control of Noise at Work Regulations 2005 - https://www.legislation.gov.uk/uksi/2005/1643/regulation/4/made
14. Why are there no learning modules, training courses or even handouts given to staff regarding noise exposure and the warnings of being exposed to such loud levels of noise?
We consult on the noise reports via Trains Health and Safety Council and at local level noise meetings so trade union Health & Safety Representatives are aware of the detail of these issues. In addition, we have provided communications on this, particularly with regard to ear defenders which have been issued for comfort. We are also working towards providing additional guidance in due course.
15. Why is the brand new Northern Line Extension to Battersea excessively and dangerously loud?
We have taken a number of noise measurements on the Northern Line Extension (NLE) before the railway opened for revenue service.
These were taken:
- Within the saloon and in the cab
- On a number of different units
- In the north and southbound directions
- in ATM and
PM modes
The results had slight variations from different units and were mostly impacted in the saloon by the state of door seals and generally by speed and curvature. The slight corrugation on the existing loop (NB) is outside the NLE proper but is being dealt with in the usual manner.
The conclusions were the trains running at full line speed exhibit similar noise profiles to other lines running at full speeds within similar tunnel sections.
The noise levels in the cabs comply with the Control of Noise at Work Regulations 2005.
16. What steps if any, have London Underground taken to ensure the driving cabs are better insulated to prevent hearing problems as well as respiratory problems for drivers?
We are not taking any specific action at this point to better insulate existing cabs to reduce noise or other changes specifically related to cab air quality. The Vehicles Engineering team are not aware of any specific problems with driver respiratory issues. However, cab seals are upgraded via planned maintenance and repairs completed when necessary.
We are currently designing new trains for the Piccadilly line. These will have better sealed cabs and air conditioning, which will potentially help with both of these factors. The air conditioning will have filters similar to those employed on the 09TS and S-stock, and better sealing of the cab is required for this air conditioning to function efficiently. These trains are expected to comply with the requirements of the LU Standard for Rolling Stock. This Standard has requirement for in train noise. Please see the relevant section attached.
17. Why have London Underground not implemented any speed restrictions in Pandrol Vanguard areas as requested by unions?
Speed restrictions have been used where necessary, which is generally where noise has risen considerably, but is still within the acceptable level, and the grinding train was not due soon enough to lower the overall noise in the area.
Determining whether to implement a speed restriction must account for a range of factors, including the impact on the level of service we are able to provide customers. Speed restrictions can often significantly reduce the frequency of services, which is deemed to have unacceptable safety and operational impacts, particularly during the pandemic when providing a high level of service is essential to enable social distancing.
We believe the controls that we have put in place are appropriate for managing any risk to train operators’ hearing.
18. Why have London Underground not implemented any speed restrictions at the Southbound tunnel between Colindale and Hendon Central on the Northern Line after repeated reports of Decompression entering this tunnel?
We have not seen any data that would suggests decompression illness is likely to occur in this section of track. As a result, we have not introduced any measures to address decompression illness on the Underground.
19. How many noise complaints on the Northern Line, have London Underground received since 2016 to present date, including those from staff and members of the public?
Please find the number of complaints in the below table. We are unable to access data prior to 2018.
| Year and Month |
Number of complaints |
| 2018 Nov |
14 |
| 2018 Dec |
18 |
| 2019 Jan |
20 |
| 2019 Feb |
21 |
| 2019 Mar |
43 |
| 2019 Apr |
33 |
| 2019 May |
22 |
| 2019 Jun |
24 |
| 2019 Jul |
41 |
| 2019 Aug |
27 |
| 2019 Sep |
21 |
| 2019 Oct |
6 |
| 2019 Nov |
2 |
| 2020 Jan |
3 |
| 2020 Feb |
6 |
| 2020 Mar |
2 |
| 2020 Apr |
1 |
| 2020 Jun |
1 |
| 2020 Jul |
1 |
| 2020 Aug |
5 |
| 2020 Sep |
3 |
| 2020 Oct |
1 |
| 2020 Nov |
2 |
| 2020 Dec |
2 |
| 2021 Jan |
3 |
| 2021 Feb |
1 |
| 2021 Mar |
3 |
| 2021 May |
2 |
| 2021 Jun |
7 |
| 2021 Jul |
10 |
| 2021 Aug |
10 |
| 2021 Sep |
3 |
| 2021 Oct |
2 |
| Total |
360 |
20. A proposed date of 2024 has been given for Pandrol Vanguard removal. This means it would have been in place for approx 8 years exposing the public to noise levels of 120dBs in certain areas.
Firstly why will it have taken 8 years to fix the problem? Secondly is this date of 2024 guaranteed?
The first 3 sites for removal of PV are set to commence in early 2022. When we first became aware of the in-carriage noise issues that PV introduced on the network, TfL engineering and track maintenance started investigating the root cause of the issue to identify how to mitigate these. There has been ongoing analysis to identify the appropriate solutions to mitigate noise issues associated with PV while ensuring we do not reintroduce residential noise, which PV successfully mitigated. As part of the investigations into various mitigation solutions, a trial was conducted on the Jubilee line where an alternative noise attenuating product, Delkor, was introduced to replace PV. The installation is a lengthy process, at an average rate of 1-2 metres per night. During the installation process, measurements had to be conducted in trains and properties, and initial results indicate that the Delkor track fastening will offer a similar benefit in terms of limiting residential noise levels, while reducing in-carriage noise, in comparison to PV. It has been identified that Delkor is a suitable option in many locations, and works are now progressing to prioritise the replacement of PV with Delkor in areas where in-carriage noise is a significant issue.
The overall date for completion has not been confirmed, however every effort is being made to ensure the suitable solution is carried out as soon as possible, taking into account TfL’s unprecedented financial challenged brought about by the pandemic.
If this is not the information you are looking for, or if you are unable to access it for any reason, please do not hesitate to contact me.
Please see the attached information sheet for details of your right to appeal as well as information on copyright and what to do if you would like to re-use any of the information we have disclosed.
Yours sincerely
Eva Hextall
FOI Case Management Team
General Counsel
Transport for London
