CAWS and ATP on Irish railways

[Junctionmad]

given that CAWS isn't a train protection system, what was the thinking in IE behind its introduction. In theory it could replace line side signals , but these are also there anyway. In the UK , at no stage was it felt necessary to repeat signals in the cab ,, alone , i.e. without intervention braking, yet UK railways are running faster trains

 

 

How extensive is CAWS in the republic ?

[josefstadt]

CAWS does have intervention braking in that failure to acknowledge a signal downgrade will activate the brakes.

[hurricanemk1c]

CAWS is on the Dublin-Cork, Dublin-Dundalk, Dublin-Maynooth and some parts of the Galway and Waterford routes. In all respects, bar signal indication repitition, it is the same as AWS.

 

ATP is used for DART services but is being combined with CAWS at the moment (Howth branch and Maynooth - Enfield are fitted)

[Junctionmad]

what I was thinking is why C - AWS. C( AWS) is essentially a warning system, Train Protection seeks to control SPADS , whereas in reality C(AWS) is really a yellow light ( caution) acknowledge system. its why southern division of BR resisted it for so long as , it had the running on yellows issues.

 

My understanding re CAWS, is that IE, does only intervention braking on downgrades to caution ( or various aspects of caution). There is no train protection on Red signals ( this is the remit of TP systems as speed of approach must be controlled to have a system that can handle intervention stop on red). ( in the UK AWS applies to distance and yellow aspects only in effect as it cannot handle SPADs)

 

 

What I was asking is why IR/IE figured it needed continuous AWS, involving installing coded track circuits , when much larger enterprises like rail track and network rail, saw that intermittent train protection systems were all that was necessary. Even the UK ATP system is non continuous . Why have CAWS and line side signals together ( in the US it was seen as a way of replacing signalling infrastructure )

 

IN fact in the US. where CAWS originated ,the railroad companies have not implemented it in any generic way. ( they dont like intervention braking anyway )

 

 

I just cant see any the much cheaper AWS wasn't used and it would have retained compatibility with NIR. Seems a rather perverse, " go it alone " decision

Edited April 30, 2015 by Junctionmad