IRSE Exam Forum

Full Version: Point Machine Location
You're currently viewing a stripped down version of our content. View the full version with proper formatting.
Hi

Should a point machine be placed only on a particular side of the Point?
My understanding is that it should be placed adjacent to the closed switch rail which caters to movement on the reverse direction. I don't remember where I read this or if I had discussed this with someone.
Is there any standard which specifies the need to place a point machine on a particular side?


P.S. please advise me if such general doubts should be posted elsewhere.

Thanks
(21-04-2017, 07:06 PM)mpr7 Wrote: [ -> ]Hi

Should a point machine be placed only on a particular side of the Point?
My understanding is that it should be placed adjacent to the closed switch rail which caters to movement on the reverse direction. I don't remember where I read this or if I had discussed this with someone.
Is there any standard which specifies the need to place a point machine on a particular side?


P.S. please advise me if such general doubts should be posted elsewhere.

Thanks

There is no convention in the UK and no technical reason to need it. There will be location specific reasons why a machine may need to go one side or another:
- other equipment to be accommodated eg backdrive
- in one areas conductor rails to avoid
- pway constraints on where the long timbers can go

Other than physical reasons, staff access is another consideration. Locating the machine in the cess as opposed to the other side of the line for people to access is an important issue.

Point machines themselves are generally configurable for Left Hand Switch Normally Closed (LHSNC) or Right Hand Switch Normally Closed (RHSNC) to give a consistent wiring interface for N or R depeding on the normal lie if a give set, but whether the machine is on N or R side makes no difference to this.
(22-04-2017, 11:48 PM)Peter Wrote: [ -> ]
(21-04-2017, 07:06 PM)mpr7 Wrote: [ -> ]Hi

Should a point machine be placed only on a particular side of the Point?
My understanding is that it should be placed adjacent to the closed switch rail which caters to movement on the reverse direction. I don't remember where I read this or if I had discussed this with someone.
Is there any standard which specifies the need to place a point machine on a particular side?


P.S. please advise me if such general doubts should be posted elsewhere.

Thanks

There is no convention in the UK and no technical reason to need it. There will be location specific reasons why a machine may need to go one side or another:
- other equipment to be accommodated eg backdrive
- in one areas conductor rails to avoid
- pway constraints on where the long timbers can go

Other than physical reasons, staff access is another consideration. Locating the machine in the cess as opposed to the other side of the line for people to access is an important issue.

Point machines themselves are generally configurable for Left Hand Switch Normally Closed (LHSNC) or Right Hand Switch Normally Closed (RHSNC) to give a consistent wiring interface for N or R depeding on the normal lie if a give set, but whether the machine is on N or R side makes no difference to this.

...and whereas I don't think NR ever does this, London Underground does place Surelock Machines in the 4 foot between the rails; I think this is the only point machine (as opposed to other types of point operation equipment such as HPSS, IBCL) for which such an arrangement is possible