Source: https://tendernation.io/opportunities/01a13bc3-2765-7213-946c-9d9ea472ede2/london-underground-central-line-audible-alarm-unit-design-replacement-of-com pending GB open procedure # London Underground Central Line Audible Alarm Unit - Design & Replacement of Combined Power Supply / Power-Amplifier Printed Circuit Board [Transport for London](https://tendernation.io/buyers/transport-for-london) Estimated value £200,000 Published 12 Sept 2025 Deadline Rolling deadline ## Who can bid - Below-threshold contract Buyers cannot shortlist bidders on suitability before tenders are in, so everyone gets to submit a bid (except some larger works contracts). [Procurement Act 2023, section 85](https://www.legislation.gov.uk/ukpga/2023/54/section/85) - Open procedure Anyone can submit a full tender; there is no shortlisting stage. ## About this tender ### 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. Read full description ## CPV classification Electromechanical equipment Alarm systems Repair and maintenance services of rolling stock Public transport services by railways Source Find a Tender (UK) · Notice ocds-h6vhtk-0599c0-2025-09-12T16:41:40+01:00 [View official notice](https://www.find-tender.service.gov.uk/Notice/ocds-h6vhtk-0599c0-2025-09-12T16:41:40+01:00) Never miss a tender like this again Get AI summaries, deadline alerts and a bid pipeline for tenders matched to your business. Free to start. 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