---
title: "London Underground Central Line Audible Alarm Unit - Design & Replacement of Combined Power Supply / Power-Amplifier Printed Circuit Board"
ocid: "ocds-h6vhtk-0599c0"
canonical_url: "https://d3tenders.com/contract/?ocid=ocds-h6vhtk-0599c0"
markdown_url: "https://d3tenders.com/contract/ocds-h6vhtk-0599c0.md"
json_url: "https://d3tenders.com/contract/ocds-h6vhtk-0599c0.json"
source: "Find A Tender Service"
current_stage: "Planning"
buyer: "TRANSPORT FOR LONDON"
published: "2025-09-12"
---

# London Underground Central Line Audible Alarm Unit - Design & Replacement of Combined Power Supply / Power-Amplifier Printed Circuit Board

Buyer: TRANSPORT FOR LONDON  
Current stage: Planning  
OCID: ocds-h6vhtk-0599c0

[View canonical contract page](https://d3tenders.com/contract/?ocid=ocds-h6vhtk-0599c0)  
[Download OCDS JSON](https://d3tenders.com/contract/ocds-h6vhtk-0599c0.json)

## Summary

Transport for London is currently in the planning stage for a tender involving the design and replacement of the Combined Power Supply/Power-Amplifier Printed Circuit Board for the London Underground Central Line Audible Alarm Unit on the 1992 Tube Stock. This procurement process focuses on identifying suitable suppliers who can design, replace, and test the necessary components to ensure continued operation and safety of the audible alarm units. Interested parties are required to complete and return a Preliminary Market Engagement Document via email by the 2nd of October 2025. The procurement falls under the industry category of electromechanical equipment, alarm systems, and public transport services by railways, with the total gross value estimated at £220,000. The contract period is scheduled from April 2026 to March 2028, with the procurement method aligned with a non-threshold utility special regime. The procurement is regional to London, UK.

This tender provides significant opportunities for businesses specialising in low-volume, safety-critical electronics, particularly those focused on electromechanical and railway systems. Companies with expertise in producing and testing printed circuit boards and those capable of managing obsolescence effectively are well-positioned to compete. The phased development model calls for initial prototyping, batch production, and the possibility of scaling, allowing businesses with strong capacity and robust assurance testing capabilities to demonstrate their strengths. Furthermore, firms with innovative approaches to long-term support in electromechanical equipment can leverage this opportunity to establish themselves as key suppliers for Transport for London.

## Notice

Scope Description The proposed tender is intended to secure LUL 92TS Central Line Audible Alarm Unit (AAU) - Design & Replacement of Combined Power Supply (PSU)/ Power-Amplifier Printed Circuit Board (PCB) updates required on the 1992 Tube Stock (92TS) Central Line of the Preliminary Market Engagement document. Context: TfL is exploring market interest and capability for remediation of 92TS Audible Alarm Units (AAU) by replacing the combined Power Supply Unit (PSU)/Power Amplifier Printed Circuit Board (PCB) inside each AAU, carrying out required factory and site testing, and returning fully functional AAUs for service. The AAU comprises two internal boards - Combined PSU/Power-Amplifier PCB Voice synthesis PCB Failures have occurred exclusively on the Power Supply Unit (PSU)/Power-Amplifier PCB, which is no longer supported by the Original Engineering Manufacturer (OEM). Given the AAU's safety-critical function, trains cannot operate without it, making obsolescence remediation essential. TfL intends to proceed in phases: Phase 1 - Development of 2 prototype combined PSU/Power-Amplifier PCB units (PCB design validation, Final Acceptance Testing (FAT) and Site Acceptance Testing (SAT)) Phase 2 - Production of 18 units of combined PSU/Power-Amplifier PCB subject to prototype approval. Phase 3 - Potential Future Demand (option) - up to 180 additional combined PSU/Power-Amplifier PCB units Objective: Identify suppliers with capability to design, replace, and test PSU/Power-Amplifier PCBs within existing AAU housings, while maintaining fit, form, and function equivalence. Understand supplier approaches to obsolescence management, aiming for 15-20 years of ongoing support. Assess capacity to deliver through a phased model: prototypes, batch production, and potential scaling. Evaluate supplier test and assurance capability, including: Final Acceptance Testing (FAT) Site Acceptance Testing (SAT) Compliance with RIA 12 and EN 50121-3-2 (EMC), and BS EN 61373 Cat 1, Class B (shock & vibration). Gain insight into market best practice for low-volume, safety-critical electronics.

### Planning Information

Engagement process description 
Please email HaliseAkkaya@tfl.gov.uk to request and complete the Preliminary Market Engagement Document. 
Please answer all questions and send your completed questionnaire by email to the Procurement Manager, Halise Akkaya ( HaliseAkkaya@tfl.gov.uk ) before 17:00 GMT on 2nd October 2025. Late Responses will not be considered. 
Non-responses to this expression of interest will be deemed as not interested. If bidders do not choose to participate in the Early Market Engagement process, this will not affect the ability to participate in the tender, if Expression of Interest to participate in the tender is received by the closing date. 
Your answers will be treated as TfL restricted in accordance with TfL standard S1782. Information security classification. This means that your answers will only be visible to people authorised by TfL, typically only the TfL staff involved in the procurement.

## Key Details

| Field | Value |
| --- | --- |
| Publication source | Find A Tender Service |
| Latest notice | https://www.find-tender.service.gov.uk/Notice/056351-2025 |
| Notice type | UK2 - Preliminary Market Engagement Notice |
| Procurement type | Standard |
| Procurement category | Goods |
| Procurement method | Not Specified |
| Procurement method details | Not specified |
| Tender suitability | Not specified |
| Awardee scale | Not specified |
| All stages | Planning |

## Dates

| Field | Value |
| --- | --- |
| Publication date | 12 Sep 2025 |
| Submission deadline | Not specified |
| Future notice date | 2 Oct 2025 |
| Award date | Not specified |
| Contract period | 31 Mar 2026 - 31 Mar 2028 |
| Recurrence | Not specified |

## Values

| Field | Value |
| --- | --- |
| Tender value | £200,000 |
| Lots value | Not specified |
| Awards value | Not specified |
| Contracts value | Not specified |

## Status

| Field | Value |
| --- | --- |
| Tender status | Planning |
| Lots status | Planning |
| Awards status | Not specified |
| Contracts status | Not specified |

## Buyer

| Field | Value |
| --- | --- |
| Main buyer | TRANSPORT FOR LONDON |
| Locality | LONDON |
| Post town | East London |
| Postcode | E20 1JN |
| Country | England |
| ITL 1 | TLI London |
| ITL 2 | TLI4 Inner London - East |
| ITL 3 | TLI41 Hackney and Newham |
| Local authority | Newham |
| Electoral ward | Stratford Olympic Park |
| Westminster constituency | Stratford and Bow |
| Delivery location | TLI London |

## CPV Codes

### Divisions

- 31 - Electrical machinery, apparatus, equipment and consumables; lighting
- 35 - Security, fire-fighting, police and defence equipment
- 50 - Repair and maintenance services
- 60 - Transport services (excl. Waste transport)

### Codes

- 31720000 - Electromechanical equipment
- 35121700 - Alarm systems
- 50222000 - Repair and maintenance services of rolling stock
- 60210000 - Public transport services by railways

## Release History

- 12 Sep 2025 at 15:41 - Planning - UK2 - Preliminary Market Engagement Notice - https://www.find-tender.service.gov.uk/Notice/056351-2025

## Documents

- https://www.find-tender.service.gov.uk/Notice/056351-2025
  12th September 2025 - Preliminary market engagement notice on Find a Tender

## Notice URLs

- https://www.legislation.gov.uk/ukpga/2023/54/contents

## Provenance

This Markdown file is an alternate public rendering of the D3 Tenders contract record. The canonical page is https://d3tenders.com/contract/?ocid=ocds-h6vhtk-0599c0. The underlying structured data is available as OCDS JSON at https://d3tenders.com/contract/ocds-h6vhtk-0599c0.json.