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POINTS AND SIGNAL CONTROL

billhaywood

Joined: 22-05-03

Topics: 17

Replies: 30

Posted: Tue 3rd May 2016, 12:23pm
POINTS AND SIGNAL CONTROL

I'm looking at placing one or two lineside buttons/switches for drivers control move points ahead. How do you avoid passengers from touching them.
 

Replies To This Post

Mick

Joined: 1-01-89

Topics: 7

Replies: 114

Posted: Tue 3rd May 2016, 2:56pm

Hi Bill,
The solution we came up with at Sheffield some years ago after an incident is to have the switch box which changes the points ahead followed very quickly by a detector in the track which freezes that command as soon as the loco passes over it. The distances have to be carefully worked out to suit all lengths of locos/tender combinations but it works. If a child on the carriages behind touches the switch nothing will happen. The photo shows the set up, the switch box is in the top left hand corner of the photo and the point it controls in the middle of the photo. Taken at a 'fun run' open day for visitors to Abbeydale from other clubs - in this case Nottingham ME.
Hi Bill,
The solution we came up with at Sheffield some years ago after an incident is to have the switch box which changes the points ahead followed very quickly by a detector in the track which freezes that command as soon as the loco passes over it. The distances have to be carefully worked out to suit all lengths of locos/tender combinations but it works. If a child on the carriages behind touches the switch nothing will happen. The photo shows the set up, the switch box is in the top left hand corner of the photo and the point it controls in the middle of the photo. Taken at a 'fun run' open day for visitors to Abbeydale from other clubs - in this case Nottingham ME.
 

billhaywood

Joined: 22-05-03

Topics: 17

Replies: 30

Posted: Tue 3rd May 2016, 6:37pm

Thank you Mick, So who what where these sensors come from then as they could be useful in other areas of the line (Woodseaves MR TF9 2AS). Would like to run them off car batteries or similar.
My (or our line) is mapped as a figure of eight enabling bi-directional running. Treating your photo as if ours, trains would come up a 1:50 gradient and pass those points in the 'right' direction. Having gone round then we would need to change the points for left. We do not want to stop and change but to keep going avoiding slippage. Then,having proceeded round we no approaching 'your' point from the left to right. So more sensors would have to be balanced in the formation. Also to stop another train from conflict of movement.
 

billhaywood

Joined: 22-05-03

Topics: 17

Replies: 30

Posted: Tue 3rd May 2016, 9:44pm

Many thanks Mick
 

Ian

Joined: 8-09-04

Topics: 0

Replies: 3

Posted: Tue 10th May 2016, 5:51pm

Hi Bill, Following on from Mick here are some details of our system. We use inductive proximity sensors. These work by inducing eddy currents in any passing piece of metal e.g. a wheel or a buffer beam and then detecting the eddy currents. The particular model we use is a Pepperl & Fuchs NBN40-L2-A0-V1. These have a range of 40mm and the trick is to get them to detect part of a passing loco or carriage without detecting the rail. Our system runs on 24 volts although these sensors work from 10-30 volts. You can find details at www.pepperl-fuchs.co.uk.
The sensors are mounted between two sleepers on an aluminium sling so that the top is at or just below rail height. The sensing face is pointing upwards and the distance from the common rail can be adjusted to prevent detection of the rail. I have included a picture to illustrate this. We use the output of the sensor (which goes to 0v when something is detected) to earth the bottom of a relay coil which has 24v via a resistor (220 ohm). The relay latches itself via another set of contacts. Another sensor will then earth the top of the coil causing it to drop out. In the case of Mick's picture the enabling sensor is some way away at the start of the section and the disabling sensor is after the pushbuttons and before the point. We use diodes in the signal wires where one sensor may be performing more than one function. Please come back if you have any further questions. Ian Cox, S&T Abbeydale MR.
 

Ian

Joined: 8-09-04

Topics: 0

Replies: 3

Posted: Tue 10th May 2016, 5:54pm

Not sure where the pic went. Trying again!
 

Ian

Joined: 8-09-04

Topics: 0

Replies: 3

Posted: Tue 10th May 2016, 6:09pm

If this doesn't work email me and I will send a copy.  Member number 03567
If this doesn't work email me and I will send a copy. Member number 03567
 

EJParrott

Joined: 30-07-13

Topics: 2

Replies: 19

Posted: Wed 11th May 2016, 5:55pm

There was someone doing stuff with printed circuit boards. Rugby need to track him down again. All we can remember is that he was at the Harrogate show a few years ago, and we're certain he came from Scotland! If I can find him again, his system may be able to help
 

billhaywood

Joined: 22-05-03

Topics: 17

Replies: 30

Posted: Wed 11th May 2016, 6:40pm

Thank you Ian, Does it protrude above rail height as I've had electric powered loco's visiting with very low mounted motors.
Thank you to EJParrot, I'd be interested to see what comes up.
Bill
 

Mick

Joined: 1-01-89

Topics: 7

Replies: 114

Posted: Sun 15th May 2016, 6:53am

Hi Bill, I can answer your question. They don't protrude above the rails, and have a cover over them after they have been fitted. Cheers, Mick.
 

EJParrott

Joined: 30-07-13

Topics: 2

Replies: 19

Posted: Wed 18th May 2016, 9:40pm

John Curtis from SMET is the man we're after...found it in an old 7.25" magazine in the archive
 

billhaywood

Joined: 22-05-03

Topics: 17

Replies: 30

Posted: Thu 19th May 2016, 11:22am

Which copy would that be thanks.
 

colinedmondson

Joined: 9-08-09

Topics: 3

Replies: 82

Posted: Fri 5th Aug 2016, 11:13pm

At High Legh the switch is more than a trains length before the point, so if a passenger does hit the switch the point will change before the train gets there. It might be annoying to have to walk back, but it is safe.
 

davidmawdsley

Joined: 1-01-93

Topics: 1

Replies: 7

Posted: Tue 4th Oct 2016, 10:01pm

We have a similar situation at Hemsby. Our solution achieves the same result, but we use a track circuit starting immediately after the push button which 'locks' the points to prevent movement when the train is approaching/passing over the point(s). This locking is only released when the track circuit clears ie when all vehicles in the train have exited the junction.
 
 
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