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.