In recent years the amount of tube noise has increased considerably. The tracks underneath Defoe was originally constructed in a way to eliminate noise above 30hz, however these frequencies can now clearly be heard. From http://www.barbicanliving.co.uk/barbican-story/construction/railway-cutting/: "The 150 mm depth of the deck is separated from the main structure by a layer of rubber bitumen, to further improve the damping characteristics of the deck. The bridge itself was placed on a transverse beam system. This consisted of two U-shaped beams, the upper one inverted, so that the legs faced each other. Rubber bearings were placed between the contact faces of the beam legs to damp out all vibration frequencies above 30 hz. There is provision for them to be inspected and the beams jacked up to allow replacement of the bearings when it becomes necessary." My questions are: 1. Is the bitumen layer still in place? 2. Are the rubber bearings still in place? 3. If so can you please release the maintenance records relating to both the above?

---

TfL Ref: FOI-1404-1819

Thank you for your request received by Transport for London (TfL) on 21 August 2018 asking for information about track repairs.

Your request has been processed in accordance with the requirements of the Environmental Information Regulations and our information access policy. I can confirm we do hold the information you requested. You asked:

The tracks underneath Defoe House was originally constructed in a way to eliminate noise above 30hz, however these frequencies can now clearly be heard. From http://www.barbicanliving.co.uk/barbican-story/construction/railway-cutting/:

"The 150 mm depth of the deck is separated from the main structure by a layer of rubber bitumen, to further improve the damping characteristics of the deck. The bridge itself was placed on a transverse beam system. This consisted of two U-shaped beams, the upper one inverted, so that the legs faced each other. Rubber bearings were placed between the contact faces of the beam legs to damp out all vibration frequencies above 30 hz. There is provision for them to be inspected and the beams jacked up to allow replacement of the bearings when it becomes necessary."

My questions are:

1.Is the bitumen layer still in place?

The bituminous layer is a ¼” waterproofing to the slab deck and is under 6” of concrete which is under the ballast.

2. Are the rubber bearings still in place?

The rubber bearings are still in place.

3. If so can you please release the maintenance records relating to both the above?

Civil Engineering assets are regularly inspected and maintenance works are carried out when / where found necessary. The inspections of these assets are up to date.

Please find attached inspection records for Covered Way(CW) 74 and CW75 which shows them to be in good condition.

Please note that the Principal Inspection report for CW75 2018 has a minor error, in that the “Date last inspected” was not updated. There was a 2013 inspection – see attached.

Please see the attached information sheet for details of your right to appeal.

Yours sincerely,

Melissa Nichols

FOI Case Officer

FOI Case Management Team

General Counsel

Transport for London

Attachments

Back to top

---