Could you please provide me with any reports/costing exercises over the last 20 years which will reveal options TfL considered for windows on the London tramlink? This should include details of the precise options TfL had (including glass thickness and protective layering options), how much they will have cost, with details on which option was chosen and why.

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TfL Ref: 2321-1718

Thank you for your request received by Transport for London (TfL) on 15 November 2017 asking for information about options TfL considered for windows on the London Tramlink. I sincerely apologise for the delay in replying.

Our thoughts remain with all those affected by the tragedy at Sandilands and we continue to do all we can to offer our support.

Your request has been considered in accordance with the requirements of the Freedom of Information Act and our information access policy. I can confirm that we hold the information you require.  You asked:

Could you please provide me with any reports/costing exercises over the last 20 years which will reveal options TfL considered for windows on the London Tramlink? This should include details of the precise options TfL had (including glass thickness and protective layering options), how much they will have cost, with details on which option was chosen and why.

Please see the attached document which forms our substantive response.

Tramtrack Croydon Ltd (TCL) was a private company that was created to design, build and operate the tramway concession in Croydon under a 99 year Private Finance Initiative. London Regional Transport, the predecessor body to TfL, over-saw the letting of the initiative, but was not involved directly in the detailed specification as this was the duty of TCL.

The trams that were selected to be used on the system were the Bombardier CR4000 trams, which are based on the same vehicles that had a proven track record in the city of Cologne, Germany. They were built to meet regulations current at the time of the signing of the Tram Supply Contract (November 1996) both in the country of build and that of intended use. Schedule 1 to the Tram Supply Contract, paragraph 26.1(iii) states that “toughened safety glass complying with BS 857 shall be employed for all windows except for Tram end windscreens which shall be of laminated glass providing adequate protection against impacts” [page 1]. Future changes would comply with the regulations current at the time of those changes.

BS 857:1967 is the British Standards Institute’s “Specification for safety glass for land transport”.

Section 8.4 of Issue 4 of the Vehicle Proposal for the CR4000 states that “all windows [in the passenger area], including those in doors, are made of single toughened safety glass of 4mm thick. They are bronze coloured and have a transparency of approximately 55%.” This is dated November 1996, and forms Schedule 3 of the Tram Supply Contract.

The submission to the HMRI of the tram specification, supported by Bombardier Eurorail, was made on 30^th July 1997.

The final CR4000 Technical Description, TB-0104-03, dated 29^th Sept 1997, agrees with the aforementioned Vehicle Proposal passenger area glazing specification in all points, apart from the transparency which has increased from 55% to 60% [pages 2-3].

Once approved, the trams were delivered from Vienna, where they were assembled, to the new depot in Croydon during 1998-99. They underwent significant testing, as did the infrastructure, in advance of the network’s actual opening day in May 2000.

We have looked back at the original as-built drawings to confirm this. All glass was originally 4mm+/-0 (external) or 4mm+/-0.2 (internal), except for the top half of the cab droplight window which was 5mm thick. The cab windscreen and quarter-lights are heated laminate glass and are therefore thicker.

It is our understanding that the following changes have occurred on the CR4000 fleet since it was built, however there is little documentation preceding TfL’s takeover of the previously private concessionaire, Tramlink Croydon Limited (TCL), in 2008.

-  In or around 2004  the arrangement of the 2 large non-opening single glass  panels each side of the tram saloon in the high floor area  just behind the cabs (indicated with arrows on page 4 of the attachment)  was changed so that the single pane was supplemented with a small hopper window positioned above a now smaller non-opening pane. Pages 5 to 6 of the attachment demonstrate this as follows:

- 23 April 2004 shows tram 2530 pre-window modification. It also still had the old electric roller destination blinds on the side and front

- 04 Nov 2004 shows tram 2545 post window modification (the first two saloon windows are now two panes, one a thin hopper). It still has roller blinds

The original thickness of the glass was 4mm. The hopper window modification was made to increase the airflow in the CR4000 tram during the summer, so 8 additional hoppers were added, 4 at each end at the high floor area. The opportunity was taken to  increase the thickness of the glass to 6mm in order to reduce the risk of a window being smashed by a thrown stone. The thickness change was carried out to the whole of  the high floor area first, with the remaining saloon windows in the lower floor area changed when damaged or vandalised. However, some non-damaged saloon windows were not replaced during this period and during the CR4000 mid-life refurbishment in 2015-17 a small number of original windows that were 4mm thick were identified.

It should be noted that this change, whilst not requested by the DfT or HMRI (now the Office of Road and Rail), did not contradict the standard to which the tram was built, or any standards that had come into force since that time. Whilst we do not hold records of the change rationale as it pre-dates TfL’s takeover of TCL, it is believed that the increase in thickness brought benefits in strength that far outweighed any disadvantageous increase in overall vehicle mass, and therefore energy consumption.

Between October 2008 and March 2009, the first, mainly aesthetic, refresh of the CR4000 fleet occurred very shortly after transfer of TCL to TfL under the Programme of Immediate Improvements (PII). We approached various suppliers for re-filming of the tram interior glass, and the buffing out of etched graffiti. The details of this are included in the following documents:

- Tram Refresh 2008 – Invitation to Tender CG [Pages 7 to 10]

- Tram Refresh 2008 - Chicago Glass Method Statements [Pages 11 to 16]

- Tram Refresh extract 2008 - Programme 28th Aug [Page 17]

One element that was considered at that time was a potential increase of the saloon door leaf glass thickness from 4mm to 6mm. However it was found that this could not be carried out as there would have been an external 2mm sharp edge between the thicker door glass and the door frame. Consequently the door glass remains the only part of the CR4000 tram glazing that is still 4mm thick, although it is filmed which mitigates loss of integrity due to shattering by projectiles.

In 2011, London Tramlink (LT) let a contract for the supply of six additional Variobahn trams, to be supplied by Stadler Pankow of Germany.  Section 6.9 [page 18 ] of Annex A1 (the “Tram Functional Specification”) of that Tram Supply Agreement requires that the “passenger saloon windows shall comply with BS 857, or a similar suitable European standard such as BN 918511”. This matches the specification required of the earlier CR4000 trams. The further paragraphs in that section go on to describe the anti-scratch graffiti window filming requirements. Section C-B of Stadler’s Vehicle Technical Description (which constitutes annex A3 of the agreement) states that the “side windows are made out of tinted safety glass (5 mm)” [page 19].

In 2012, LT re-tendered the contract for reactive interior filming of the entire tram fleet saloon glazing in order to prevent scratch graffiti. A further benefit of the film was the retention of a shattered window pane in “one” contiguous mass, although the toughened glass is designed to crumble without shards or splinters in the event of breakage.

- LT-C-12-070 TL Window Filming Scope - Refresh V.3 [Pages 20 to 27]

- LT-C-12-070 Contract Returns Evaluation matrix [Page 28]

In 2013 we trialled and commenced the installation of a similar protective film on the Stadler Variobahn cab sash and quarter-light windows to prevent the glass splintering when hit by stones from outside. The following modification panel papers contain the rationale and approval for these changes:

- LT-Mods-13-008 Stadler tram cab droplight window filming – Trial [Pages 29 to 32]

- LT-Mods-13-042 Stadler Tram Cab window filming - fleet [Pages 33 to 36]

In terms of standardisation, the mid-life refurbishment programme of the CR4000 trams which took place between November 2015 until March 2017 has resulted in the windows of the CR4000 fleet to be completely 6mm thickness (except for the saloon door glass of those trams as previously mentioned).

No changes to the Variobahn fleet’s glazing thickness has occurred since purchase, and that fleet’s number has now grown from the original six to 12.

In addition, since the tragic overturning of a tram in November 2016, we have been working with safety experts to test various options to improve the containment provided by tram windows and doors.

In accordance with the FOI Act, we are not obliged to supply some of the information as it is subject to a statutory exemption to the right of access to information under section 43(2). In this instance the section 43(2) exemption has been applied to the pricing information contained within the document, as it would be likely to prejudice our commercial interests and those of the suppliers who tendered for the contract.

The use of this exemption is subject to an assessment of the public interest in relation to the disclosure of the information concerned. We recognize the need for openness and transparency by public authorities, particularly where the expenditure of public money is concerned, but in this instance the public interest in ensuring that we are able to obtain the best value for public money outweighs the general public interest in increasing transparency of our processes.

Please note that in accordance with TfL’s obligations under the Data Protection Act 1998 (DPA) some personal data has been withheld, as required by section 40(2) of the FOI Act. This is because disclosure of this personal data would be a breach of the DPA, specifically the first principle of the DPA which requires all processing of personal data to be fair and lawful. It would not be fair to disclose this personal information when the individuals have no expectation it would be disclosed and TfL has not satisfied one of the conditions of Schedule 2 of the Data Protection Act which would make the processing ‘fair’.

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

Sara Thomas

FOI Case Management Team

General Counsel

Transport for London

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