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

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.