Enabling Magnetic Track Brakes on GB Mainline Rail

Transcription

1 Enabling Magnetic Track Brakes on GB Mainline Rail RSSB Research Project T1099 Presentation to V/T SIC Annual Seminar, 31 st January 2017 Liam Purcell, Senior Consultant, Ricardo Rail

2 Introduction: What Are Magnetic Track Brakes? Magnetic Track Brakes (MTBs) are a form of brake, mounted on the bogie frame between the wheels When the MTB is lowered to contact the rail, a magnetic clamping force is developed between the MTB and the rail. Friction between the MTB and the rail creates a braking force which contributes to train deceleration. + Improve braking performance + Beneficial in low adhesion + Optional / complementary technology to sanders No benefit in traction Image credit Alan Lawton 2

3 What Did the Research Set Out To Achieve? MTBs widely used in Europe, and on GB Tramways: but not on GB Mainlines Why? Need a consistent approach. Called up by Infrastructure TSI The research is a precursor to the drafting of a new Railway Standard to enable the use of MTBs on GB Mainline Rail The project objective is to deliver a detailed feasibility assessment of MTB deployment on GB Mainline Rail, considering: Application scenario Cost-benefit analysis Technical compatibility Short timeframe (kick-off meeting to final deliverables in six months) 3

4 MTB Basics; Low vs High Suspension Low Suspension 6-12mm clearance Activated by energising electromagnet Time ~0.5 seconds More suited to Light Rail / Tram High Suspension mm clearance Activated by air cylinders Time ~ 2 seconds More suited to Mainline application Images credit Knorr Bremse 4

5 MTB Basics; Rigid vs Articulated Rigid Single piece pole shoe Simpler, cheaper Performance tails off with speed More suited to Light Rail / Tram Image credit Knorr Bremse Articulated End pieces and intermediate pieces Pieces can move to align conformably with the rail head More suited to Mainline applications Image credit Alan Lawton 5

6 MTB Basics; Operation & Specification Operation Current is passed through a coil wrapped around the pole pieces Magnetic field flows through railhead (via small air gaps) MTB tends to self-centre over the railhead Very little leakage of the magnetic field outside railhead Specification: Typically 1.2 m long Approximately 1 kw power consumption Magnetic attraction / clamping force 85kN Pole pieces steel / iron / sintered Eddy Current Brakes are fundamentally different! 6

7 MTB Basics; Example Performance: Normal & Low Adhesion Conventional Brakes (13%g) Low Adhesion: Conventional Brakes + every bogie with MTB (6.4%) Conventional Brakes + every fourth bogie with MTB (15.7%g) Low Adhesion: Conventional Brakes + every fourth bogie with MTB (3.1%) Conventional Brakes + every bogie with MTB (24%g) Low Adhesion: Conventional Brakes (2%) Emergency Braking Distance from 50mph Braking Distance From 50mph (Emergency Brake) Normal Adhesion Very Low Adhesion Normal Adhesion: Conventional Brakes + every bogie with MTB (24%) Conventional Brakes (2%g) Normal Adhesion: Conventional Brakes + every fourth bogie with MTB (15.7%) Conventional Brakes + every fourth bogie with MTB (3.1%g) Conventional Normal Adhesion: Brakes Conventional + every Brakes bogie (13%) with MTB (6.4%g) T1046 estimated 63% of low adhesion incidents prevented by a 1%g improvement MTBs might condition rail / remove contaminant 7

8 Project Approach Initial Questionnaire (29 responses from 33 recipients) 17 Readily Identified Mitigations Longitudinal Forces Proposed Mitigations Start Detailed Questionnaire (targeted 11 organisations) Industry Workshop (21 compatibility issues) Rail Discontinuities Switch Lifting Signalling Compatibility Compatibility Checklist Case Study (St Pancras to Corby) End Economic Case 8

9 Findings: Application Scenario The research recommends that MTBs should be allowed on GB Mainline Rail infrastructure Although use should be restricted such that they are only used as a supplementary brake in emergency braking scenarios Or in circumstances where a manual MTB application by the driver could avoid an emergency brake deployment The research recommends that MTBs should not be used for normal service braking 9

10 Project Impact and Benefits & Where to Find Out More Successful research project Identified the potential issues Developed mitigations for majority of issues Identified areas to focus on for technical compatibility Foundation for drafting a new Railway Standard to enable the use of MTBs on GB Mainline Rail The report and further information on RSSB project T1099 can be found on 10