RSSB2759 - T1163 Criteria for assigning differential speed categories - Supplier Engagement Day

RSSB is holding a Supplier Engagement Day on Friday 4th January from 13:30 - 15:30 at RSSB offices in London.

Should your organisation wish to attend or dial in to this meeting you must email the following email address with the name of your organisation and those who are to attend by COP on Thursday 3rd January: Shareditt@rssb.co.uk Dial In Details: Number: 0203 142 5510 Conference ID: 720572 -- Invitation to pre-tender meeting T1163: Criteria for assigning differential speed categories Background This project aims to produce evidence based criteria to determine for the speed differentials MU, EMU and DMU with respect to both rolling stock and infrastructure.

Various lettered speed differentials are implemented across the GB rail network.

These are a permission to run above line speed and offer a proven way of enabling speed increases for specific rolling stock.

However, with the introduction of new fleets and significant infrastructure works the application rules need to be clarified.

Differentials are dependent on the characteristics of the rolling stock and the infrastructure (principally track conditions) where the characteristics of the rolling stock and infrastructure combined are such that the trains can travel at high speeds without causes track degradation at unsustainable levels.

There is little documented criteria for applying these differentials and there seem to be different approaches taken to suit local rolling stock/infrastructure features at the time with some of the rationale that determine differential speeds are well known and some less so.

Previous research by RSSB (T996: Categorising the relationship between track condition, line speed, and vehicle forces) looked at the Sprinter (SP) category and following a thorough methodology the application rules from a rolling stock perspective are now clarified.

As part of the previous work the locations of other differential speeds was compiled and forms a useful component of this follow on work to investigate the MU, EMU and DMU categories.

High level objectives This project will develop a suite of application rules to establish clear criteria for the application of MU, DMU and EMU differential speeds to both rolling stock and infrastructure.

The criteria will be used to assess both existing rolling stock and can be used as a design reference for the specification for new fleets.

The infrastructure rules will set out criteria for application of differential speeds to infrastructure which can be used for applying a differential speed and raising/removing a differential speed.

An important part of the work will include developing a business case framework to demonstrate real world examples where the application/amending of differentials can lead to improvements in terms of journey times, capacity or reliability improvements.