A NEW APPROACH TO OHL

Railway Engineering Conference
London June 2005

Extent of Electrification

• In EU, UK almost lowest % of track
• Energy source flexibility
• Lower pollution (modal switch)
• Lower operating costs
• Lower train maintenance costs
• higher vehicle reliability

OHL Functionality

Reducing costs

• single OHL wire    - but sags
• larger diameter (14mm) (150sq.mm)    - but higher unit weight
• Fewer support masts    - larger sag or higher tension in OHL
• simpler suspension system    - no registration arms    - different tensioning

Prototype installation

• Carnforth Railway Centre
• 1200m of single track
• curved
• mixed use
• existing overbridges
• high HGV loads underneath

Erecting masts and first OHL hang

Mast And Suspension Detail

Prototype May 2004

Mast and suspension: Nov. 2004

OHL Over Track Following Curve

Conventional Tensioning OHL

New Tensioning Method: Side Tensioner

Tensioner Using 50kg To Achieve 30000kN In OHL

Design and Installation

• Track curves min. radius 200m
• mast spacing reduced to 30m
• 2 Over bridges
• one direct suspension, other span wire
• OHL run out over whole length
• on temporary mast pulleys
• OHL tensioned and clipped up
• 300m at a time

New and Old : Installation

Practicalities

• Weather – December 2004
• no exclusive track access
• cherrypicker over parked rail vehicles
• getting right alignment
• using temporary ropes to lift and clip
• total installation 40 man days
• final clipping 3 man days
• total costs £50k for 1200m

Installation and Isolator

Conclusions

• OHL can be simplified
• OHL costs can be reduced
• Elastic supported single wire
• good for speeds to 150km/hr
• Low electric resistivity can be achieved
• Jan.2005 severe storms – no damage
• could be used for branch lines
• reduce cost of new light rail projects ?

A Future For UK Light Rail ?

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