Eridge (P4) rebuilding

by 10800

original page on Old RMweb

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Comment posted by pinkmouse on Mon Apr 27, 2009 3:27 pm

Yup, first board done in very fetching pink and black.

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??? posted on Mon Apr 27, 2009 3:31 pm

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??? posted on Sat May 02, 2009 5:02 pm

Steady progress being made on ballasting and tracklaying on all the plain track sections. This was all done before the discovery of the use of Johnson's Klear for ballasting

Once the plain track is done, the P&C work will be done ex-situ and ballasted after fitting. In fact the first bits are under way now, so there may be some pics of that soon.

When the trackbed boards were cut we were using a Templot printout based on A3 sheets joined together. Despite care in joining the individual sheets, there was a offset discrepancy of about 2 inches over the 25 ft overall length discovered when we used a single roll-plotted printout. Fortunately the turnout on the left foreground here is only a trap point so we can just get away with it.

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Comment posted by martin_wynne on Sun May 03, 2009 3:51 am

Hi Rod,

That's an error of 0.67% which I would regard as significant.

Templot includes a printer calibration function for the highest accuracy when printing directly. But it's not available for exported DXF files, and using it with commercial PDF printing firms means a double trip to the print shop.

For DXF files you can make your own correction via the print scaling function, but again it means two trips to the printer (and adding some background reference lines to the file).

The most likely causes of a mismatch are:

1. Use of a laser printer instead of ink-jet or other cold printer. Laser printers heat the paper, causing it to shrink and distort slightly. Ink-jet printing is recommended for the highest accuracy when printing from Templot.

2. Uncalibrated roll printer. Over a 25ft length any variation from the quoted dpi figure can be significant. On a heavily-used commercial printer the most likely cause is wear of the print roller.

3. Wide variation of ambient conditions in which the paper or printouts were stored. For laser printing, paper which has been stored in damp conditions will shrink noticeably when printed.

Sorry to hijack your topic, I'm never quite sure of the correct form to adopt when responding to a side issue like this. The layout is looking good!

regards,

Martin.

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Comment posted by pinkmouse on Sun May 03, 2009 8:49 am

Martin, I doubt very much that any of us involved in Eridge consider it a hijack.

This is however interesting information about the issue of laser printers, it is something I had in the back of my mind from using a laser to create PCB artwork, but as I don't work with the very tiniest of SMT components with the tight tolerances involved, it was never an issue, however I can now see how it creates problems with a design on such a large scale as this. Still, nothing we can do about it now, just something to bear in mind for Eridge MkIII.

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??? posted on Sun May 03, 2009 1:07 pm

Hi Martin

Maybe you misunderstood me, or I expressed it badly, it wasn't an error in overall scaling, just a lateral shift due to (my) cumulative errors in sticking a lot of A3 sheets together when we cut the baseboard tops compared with the single roll plot being used now for trackbuilding. Lengthwise it was spot on.

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Comment posted by craigwelsh on Mon May 04, 2009 10:23 pm

Looking good Rod, we'll be going through all this in a couple of months when we start relaying the main lines on Slattocks following the S4 Soc AGM..

I've had access to a 42inch wide roll plotter so we used that to print out the yard and it will be used for the main section, it certainly is a lot easier than sticking bits of A3 together.

We've been relaying the yard but keeping the points in place and it proved 'interesting trying to tie the Templot print out to the points that had been laid. Hopefully it'll all be working again by the AGM though.

Interesting how you ballast all the sleepers before laying the rail.. I assume these are all still 1/2 height sleepers?

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??? posted on Mon May 04, 2009 10:54 pm

Thanks Craig

Yes they're half-height sleepers with rivet holes, which help in placing the rail (once ballasted you can't see the Templot print any more ) although rivets aren't being used on the plain track, just Exactoscale chairs glued to the sleepers. P&C work is being done separately before ballasting and using rivets at crossing vees etc.

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??? posted on Sat Jun 13, 2009 4:51 pm

Some pointwork now being installed in between the lengths of plain line

And a couple of shots showing the board-end "track strengthening" process - PCB with brass bar onto which sleepers are threaded (if we remember ) and rail is soldered to. The sleepers are currently loose but will be bedded into the ballast and cosmetic half-chairs added in due course.

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Comment posted by Captain Kernow on Sat Jun 13, 2009 9:21 pm

Hmm, interesting.... food for thought, I think...

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??? posted on Sat Jun 13, 2009 10:07 pm

The idea is that (unlike just soldering the rail to copperclad) you can still use chairs and maintain a gap between the rails and the sleepers.

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Comment posted by jim s-w on Sun Jun 14, 2009 9:32 am

Looking great Rod

Are you sure the check rails and wing rails wouldn't be combined in a crossing though? I dont know about your era but they sometimes are now a days.

Cheers

Jim

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??? posted on Sun Jun 14, 2009 5:01 pm

Jim, presume you mean extending the wing rails to be the check rails for the opposite crossing? It seems logical in some respects, but I haven't seen it done much in the 50s/60s even if it only means leaving a short gap.

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Comment posted by jim s-w on Sun Jun 14, 2009 5:04 pm

Thats right Rod

I did wonder if it was a more recent thing.

Cheers

Jim

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Comment posted by Andy G on Sun Jun 14, 2009 8:27 pm

It was quite common in the Manchester area in the 50s and 60s and Slattocks will feature them, but it does seem to be a case of checking the prototype at the appropriate date.

Andy

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??? posted on Thu Jul 23, 2009 4:49 pm

While having a few days off I'm cracking on with building some of the Eridge pointwork ex situ.

This is the crossover from the down loop into the goods yard, with trap point and entry to the end dock. Here's the Templot printout laid out with ply sleepers already in position (rivets on a few of them). This is actually the bit nearest the camera in the very first photo in this topic on the old version of the layout.

After planning out and threading on the chairs - including key direction, as this is bidirectional I opted for alternating except next to fishplates where the keys have to be pointing the other way - I decided to solder on the brass fishplates before laying the rail (in places where only a cosmetic rail join is needed). Despite the Brassmasters packet these are old Colin Waite ones. The steel rail is quite old too, hence the rust - realistic huh?

First 'straight' stock rail fixed, covering two turnouts.

First vee (1:8) in position, gauges in place (the block gauge just acting to stop the nose of the vee going tight to gauge with respect to the stock rail).

And the vee in place. The red marks are where physical rail joins are required, not just cosmetic ones (for polarity control).

Hopefully more to come tomorrow (off out to the jazz tonight )

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??? posted on Sat Jul 25, 2009 7:44 pm

It's really spooky to see someone else's version of the same prototype! Ralph Burrows' depiction of Eridge in MRJ 192 is very nice indeed, but he did have six years start on us, and I presume he hasn't torn it all up and started again either!

It doesn't say what gauge it is, although I guess it's 00 just from the references to moving straight from Peco to copperclad and to using RTR stock without mentioning conversion - so that would speed things up as well.

It says something for the operational interest in the prototype, because that is four versions that I know of - this one, ours, Vivien Thompson's somewhat disappointing one that was in RM a couple of years ago, and another home-tied EM version somewhere in Cheshire (which I think is set in LBSCR days).

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??? posted on Mon Jul 27, 2009 1:26 pm

More on the turnouts

The Martin Wynne (well that's where I got it) method of forming obtuse angles in wing rails - couple of rail offcuts, small screwdriver, jeweller's hammer, light tap and there you are (only two hands and no tripod available so no action shots!)

Wing rail being fitted using flangeway, triangular and block gauges - spot the mistake (rectified later ) in the last chair on the right!

Exactoscale insulated fishplate in place for the switch rail

Switch rail fitted, and completed common crossing (will do check rails later)

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??? posted on Sun Aug 30, 2009 1:03 pm

A couple of shots showing a bit more tracklaying progress - now almost got one line complete end to end

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Comment posted by Dave Holt on Sun Aug 30, 2009 3:06 pm

Rod,

This is looking very nice, indeed, look forward to further progress. The sweep of the curve on the main line is just crying out for a re-built West Country with 12 on, flat out! - And I've got just to loco!!

Keep up the good work.

Dave.

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??? posted on Sun Aug 30, 2009 4:28 pm

Thanks Dave, we might borrow your WC one day!

It would have to accelerate pretty sharpish out of the (extended!) fiddle yard though, and the 12 on might have to be mainly Gresley or Thompson (?) bogie pigeon vans for authenticity - passenger services usually only went to 7 or 8.

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