robin stevens - queensland rail - presentation 2 - design location, catchpoints and junction

Robin StevensTeam Leader Track Design Queensland Rail

Infrastructure location and Drainage

• Common Sense

• Bigger Picture Overview

• Working Together

• There is no substitute for correct turnout location & construction in attaining high long term reliability.

• It is almost impossible to rectify poor design and construction via maintenance processes

• Compared with other trackside or infrastructure equipment, points failures will invariably account for the greatest delays to train operations, therefore location, drainage and accessibility is critical.

• Basic Renewals

– Need

– Integration with other works

– Transition opportunity

– Correct existing deficiencies

– Review current performance issues

– Operational improvements

– Technological improvements

• Greenfield Sites for Turnouts

– Eliminate Horizontal curvatures

– No Vertical Curves

– Formation & Drainage

– Clearances

– Access

Result of turnout on a curve

• Vehicular Access

– Permit a suitable hiab truck or crane to travel safely to the turnout

– Access road should be weather resistant and suitable for heavy vehicles

– Permit a hiab truck or crane to unload

– Permit a hiab truck or crane to turn around

– Allowance to pass other structures

The cess is not wide

enough to permit

vehicular access to

the turnout.

Small vehicles, in this

case, can get close to

the turnout. Larger

vehicles or crane

trucks can not.

Access

Suitable access permits a hiab

truck to access adjacent to the

turnout, allowing new and old

material to be loaded directly onto

the track, thereby reducing manual

handling, time and resources

Well Designed Access

Track Access is Critical for the

Installation & Maintenance of Infrastructure

Walkway material has

been spread along the

track covering the

components and

preventing normal

inspections

Walkway material has been

spread over the ballast and

will eventually cause

ballast/formation failure by

preventing water to escape.

Driver Walkways

Note the walkway permits,

for the mechanised tamping

of the track

Driver Walkways

Safe Operation of Points

Level area for stable footing

when operating manual

lever

• Drainage

– Loss of vertical geometry

– Loss of horizontal geometry

– Formation of “bog holes” and track pumping

– Sleeper/Bearer failure

– Rail breaks

– Derailment

Drainage

Turnout located on top

of embankment

Drainage

DrainageEmbankment

slippage

Blocked cess

drains

Embankment

erosion

Poor

drainage

resulting in

fouled ballast

and sleeper

pumping

• Catchpoints used to intentionally derail a train

rather than let it cross onto another track

– Fitted at end of

• Yards

• Loops

• Refuges

• Junctions

• Catchpoints comprise a single switch and

stockrail assembly, ramp block and throw-off

rail.

Ramp block

Switch assemblyThrow-off rail

Ramp block

Switch assemblyThrow-off rail

• Catchpoints design must include

– Safe landing area

– Clearance from main line

– Account for:• Train type

• Train speed

• Risk to both infrastructure and personnel

• Catchpoint with safe landing area

Run out area shall provide

clearance to all structures and be

a minimum of two vehicles in

length

Catchpoint Landing Area

Catchpoint with Insufficient Landing Area

Catchpoints

• Catchpoints with unsafe landing area

Catchpoints & Structures

Catchpoints

Catchpoint Derailment

Case Study

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• Common Sense

• Bigger Picture Overview

• Designers on sites

• Working Together to

Achieve the Best Result