The following statements were released by the Tram Team to the coalition of the four community councils along the tram line extension. They address the delay around the conclusion to the final design, not the quite separate (noise/vibration) issues that may occur during construction.
I can confirm that we are expecting the outstanding design submission by the end of next week (26th Feb) at which point we will have a 3 week review period to go through the submission (this period is set out in the contract). On the basis that the information is provided and is accurate, we would anticipate getting the report finalised by mid to end March. I am continuing to see if we can accelerate timescales but as I have said before this is not within our control as the contractor is working to an agreed design programme. I will of course keep you posted as more information becomes available.
[…] We are having to work within prescribed design approval timescales which means the matter is not being closed out as quickly as I would like, that said, work is underway with Atkins and I thought a short progress note would be useful ahead of your community council meeting this evening. It is worth noting that the team continues to work under Covid-19 restrictions affecting all of us, this has inevitably had an impact of some of the design packages meaning we have had to prioritise design approvals to align with the construction programme.
As you know the matter arose following observations raised by Prof. Thompson in relation to a specific property on Leith Walk. I subsequently met with the property owner and representative of the community council to discuss the issues raised.
The issues are twofold. Firstly, there are specific queries around the Leith Walk property and the conclusions reached in relation to vibration. Secondly there are more general queries relating to ground borne noise (GBN) on the line.
On the back of the meeting, we asked Atkins, the Council’s technical advisor, to liaise with the contractor and the contractors design team to address the vibration queries and to also provide some commentary on ground borne noise.
On the first point, Atkins are still awaiting final design information from the contractor to be able to provide a definitive view on the proposed design, this has been through several iterations, which is not unusual, and we anticipate having the last of the information in the very near future. On a positive note, Atkins have confirmed that the track system being brought forward is from a very well established company in the field of track components (Pandrol) and that they will be able to supply whatever vibration attenuation measures that the contractor specifies.
As well as addressing the specific questions raised by Prof. Thompson, we have also asked Atkins to confirm whether, taking a conservative approach, there are any instances where vibration would exceed the design standards specified under the contract, I am hopeful they will be able to provide a definitive answer to this once they are in receipt of all the design information. We have also asked them to set out and explain the standards adopted by the project.
With regards to ground borne noise it is common on light rail/tramways not to state limits as the GBN contribution is likely to be insignificant in comparison to the air-borne noise contribution for which limits are specified in the contract. We have however asked Atkins to research other light rail schemes to confirm this point and to also discuss the matter with the contractor and the contractors design team. The purpose of this is to provide greater certainty for people whose properties are close to the line and have concerns about ground borne noise levels. This will be included in the Atkins report.