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St Albans South - Works in 2016

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Re: St Albans South - Works in 2016

Unread postby John Webb » Fri Nov 18, 2016 8:49 pm

Other work recently undertaken has included extending our garden railway:
Image
Although it looks as though we're going to have to develop our own "Rail Head Treatment Train" to clear the line of leaves....

Partly to protect the track at the back from greenery, we've built a cover over the track and decorated the ends with a tunnel mouth:
Image
Hopefully we'll try and add a few signals.

Regarding the 'Wild Life' in a previous post, having cut back more greenery this week, we were able to inspect more of the wood ducting. Another nest site was found, but there had been no damage to the wires, I'm pleased to say!
Last edited by John Webb on Tue Nov 22, 2016 6:48 pm, edited 1 time in total.
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Re: St Albans South - Works in 2016

Unread postby JRB » Fri Nov 18, 2016 10:40 pm

Be careful. Some voltage will be induced from the nearby 25kV. That's one reason why pole routes did not survive electrification, even when they were still thriving elsewhere.
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Re: St Albans South - Works in 2016

Unread postby Richard Pike » Fri Nov 18, 2016 11:00 pm

And your arresting arrangements for lightning are well catered for. Nothing worse than lightning making it's own mind up where to go. Does each pole have an earth wire starting as a coil on the butt? I note a spur to the box. Are there lightning arrestors in the box? Nice looking job though.
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Re: St Albans South - Works in 2016

Unread postby John Webb » Thu Nov 24, 2016 3:59 pm

JRB wrote:Be careful. Some voltage will be induced from the nearby 25kV. That's one reason why pole routes did not survive electrification, even when they were still thriving elsewhere.

Richard Pike wrote:And your arresting arrangements for lightning are well catered for. Nothing worse than lightning making it's own mind up where to go. Does each pole have an earth wire starting as a coil on the butt? I note a spur to the box. Are there lightning arrestors in the box? Nice looking job though.

Gentlemen, thanks for your comments. The lines are completely detached from anything, and regarding induction from the 25kV OLE, we are some 10 yards from the two return/booster wires and 15yards from the nearest running line. It is my intention to make some measurements at some time just to see what they do pick up!

Re lightning - one member who is a qualified electrical engineer, and in particular knows a lot about lightning protection from working on outside broadcasts for the BBC, reassures us that the isolated wires are unlikely in our circumstances to be a problem. He considers the finials on the roof of the box, the OLE supports and the trees around much of the site, are more likely to attract lightning due to their greater height and better earthing.
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Re: St Albans South - Works in 2016

Unread postby Richard Pike » Thu Nov 24, 2016 6:09 pm

I have a bit of pole route next to the East Coast Main Line near Arlesey. Having been out there in a storm and seen lightning hit a telegraph pole rather than the thumping great stanchions supporting the 25 KV overhead wires i feel it's anyone's guess as to where it will go. On another occasion at the same location the GPO pole was split down the middle by strike, the phone in the residence was almost unrecognisable and a cable in the High Street had a hole burnt through it's insulation mid length between two manholes. I worked for BT at the time and was on the gang that recovered the old and pulled in the new. Sections of that cable are still in use between my boxes at home.

Another encounter with lightning was at Hilgay signalbox. The storm was beyond Downham. The instruments had a definite twitch every time there was a flash. I was invited to look at the lightning arrestors downstairs. I wasn't so close for the second flash i witnessed across them.

My signals have been in the back garden since 1986. As far as i'm aware i've not encountered a direct lightning strike. I do however sometimes find i have minor faults in the telephone type gear the simulator is made from after a storm.
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Re: St Albans South - Works in 2016

Unread postby Richard Pike » Thu Nov 24, 2016 6:33 pm

As an aside. How many preserved lines come within the immunisation boundary of 25 KV traction systems? The Nene Valley, K&WVR are two that spring to mind.
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Re: St Albans South - Works in 2016

Unread postby John Webb » Fri Nov 25, 2016 8:38 am

Richard Pike wrote:As an aside. How many preserved lines come within the immunisation boundary of 25 KV traction systems? The Nene Valley, K&WVR are two that spring to mind.

Out of curiosity, what is the immunisation boundary distance?

Thanks for your other comments, Richard. We will bear them in mind.
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Re: St Albans South - Works in 2016

Unread postby JRB » Fri Nov 25, 2016 9:13 am

I think a lot of this was discussed in connection with Thameslink around the system boundary.
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Re: St Albans South - Works in 2016

Unread postby Richard Pike » Fri Nov 25, 2016 12:06 pm

Another little story this time about the 25KV. I took my lad to Peterborough to watch trains. He was aged about 4 or so. At the end of the platform there had been erected one section of building site type fence sitting in two rubber blocks. My lad touched it. I heard the spark and saw him recoil rather alarmingly. I touched it soon after and could feel it had some potential and was being 'charged up' by the 25KV. It was reported to station staff who came down and touched it, at a somewhat longer interval than me after my lad had discharged it, and he got a - good belt. The next call was to the ECO and within 30 mins or so someone from the overheads came out and tested it, first by touch (and he couldn't hide the good news) and then with a hand held device. It gained a clamp on earth strap until it could be removed. I heard the OLE guy saying on the phone he wanted an isolation to remove it from the platform.

Bear this in mind when going near you copper wires up the poles, especially if they are insulated from each other and from earth.

All this sounds rather negative but i don't mean it to be. It looks superb.
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Re: St Albans South - Works in 2016

Unread postby JRB » Fri Nov 25, 2016 9:59 pm

Drifting from the St.Albans subject further (new thread?) there was the man who ran his soil heating cables from his lineside fence and was apparently prosecuted for stealing electrical energy. Otherwise, St. Albans S. could be powered from induction.
Last edited by JRB on Sun Nov 27, 2016 10:38 pm, edited 1 time in total.
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Re: St Albans South - Works in 2016

Unread postby John Webb » Sun Nov 27, 2016 9:37 pm

JRB wrote:Drifting from the St.Albans subject further (new thread?) there was the man who ran his soil heating cables from his lineside fence a nd was apparently prosecuted for stealing electrical energy. Otherwise, St. Albans S. could be powered from induction.

It's worth a comment that we've not, as far as we are aware, suffered from induced currents/voltages. Our computer simulators (our new Raspberry Pi system is now mostly active) have always used pull-up resistors for inputs not operated, and pulled down to 0 volts to indicate operation - this seems to have worked OK.

Probably the last pictures of work this year - we've been suffering leaks around the two finials on the box roof - last Wednesday saw a dry, if cloudy day, and we hurriedly got the ladders out:
Image

Our chairman is seen here painting the North finial, after applying mastic round the top of the lead flashing:
Image

And the South finial gets similar treatment:
Image
It is actually the first time the finials have been repainted since the initial restoration in 2007/8.

We've put the MR pole route and the LED signal display in as entries for this year's Heritage Railway Association's annual awards scheme, and await hearing if we've had any success.
Last edited by John Webb on Wed Nov 30, 2016 9:40 am, edited 1 time in total.
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Re: St Albans South - Works in 2016

Unread postby Alistair Larter » Mon Nov 28, 2016 6:43 pm

Great job. Pleased you got them sealed before winter.
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Re: St Albans South - Works in 2016

Unread postby John Webb » Mon Nov 28, 2016 10:09 pm

Alistair Larter wrote:Great job. Pleased you got them sealed before winter.

So are we!
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Re: St Albans South - Works in 2016

Unread postby scarpa » Sat Dec 3, 2016 12:56 pm

The Cholsey and Wallingford railway their Bay platform at Cholsey is next to the new OHL route shortly to be completed along the Relief lines.The Main lines have been energised when required already.
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Re: St Albans South - Works in 2016

Unread postby John Webb » Thu Dec 8, 2016 5:51 pm

Back in 2009 we came up with a means of operating a microswitch by a reversed lever, using a chopped-up and rebent wire coathanger:
Image

These (the Heath Robinson Mark 4) have served us reasonably well, but a while back we decided a more robust system was needed, and came up with microswitches mounted on bars clamped to the frame:
Image

The above shows the result of work during the year, work will continue into 2017.

We're also amending the microswitches on the levers still fitted with downrods, also work still in progress:
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