Eastwood Town - A tribute to Gordon's modelling.

[gordon s]

Thanks Alan for your concern.  I'm really glad you guys flag up these things as I do have selective blindness every now and again.  Even more thanks to Ian for confirming what I was thinking.  The 32" radii curves are well hidden from view, so I can deal with that even though it meant dropping my 36" radius rule.  I have around 20 professionally built loco's with the rest of them RTR stock.  I'll need to check the kit built loco's but I feel they will be OK, whereas RTR won't be an issue.

 

If it really becomes a problem then I'm quite happy to hand build a few lengths of plain track and widen the gauge if necessary to cope with rigid long wheelbase chassis.

 

OK, back to the bridge....

 

Thanks again for your efforts Martin.  It all makes sense now.

 

Here's the overall board plan set on my wife's new rug that cost four C & L turnouts.  Those of you reading John's thread on C & L will get the joke....

 

 

....and here's the detail based on Martin's realignment of the single track.

 

 

I had to print it out full size to see what impact it has.  Now I can see the slightly asymmetric alignment of the single track, which doesn't give me a problem.  It all makes sense now, Martin.

 

Having spent the morning shuffling between keyboard and kitchen floor, I'm going off to the garage to knock up some ply bits and bobs to fabricate the bridge before cutting a new ply track bed.

 

I still have one question buzzing round my head though and that revolves around the transition between the bridge supports and the retaining walls.  If both of those are set at a slight angle, say leaning back 5 degrees, that will create a compound angle at the point where the bridge support and retaining wall meet.  Not a problem at all cutting that in a bit of ply, but I am curious how that would have been dealt with in full size using stone or brickwork.

 

Would there have been a pillar as I suggested earlier or would there be some other structure to accommodate the join?

Edited January 23, 2016 by gordon s

[gordon s]

Just to complete the picture.  I cut some side walls from 18mm chipboard to see how they would stack up.  They will be cut down to accommodate pad stones etc but are fine for illustration purposes.

 

The track line is fine and it's a shame the standard Peco girders are just a fraction too short, overhanging the supports by just a few mm, not the 20mm required on each side.  If I understand correctly and these supports need to be canted back slightly, then that overang will reduce further as the supports cant backwards.

 

Looking through Bridges for Modellers most of the bridge support piers appear to be vertical, so were you only referring to the retaining walls that run alongside the double track?

 

 

 

 

[PhilH]

Scratchbuild the bridge sides, easy, quick and bespoke.

 

Plasticard is your friend.....

[martin_wynne]

Looking through Bridges for Modellers most of the bridge support piers appear to be vertical, so were you only referring to the retaining walls that run alongside the double track?

 

Hi Gordon,

 

Yes, on reflection I think you should have the abutment walls vertical. I was imagining that the tracks were on an embankment, with perhaps low retaining walls at the base. I didn't realise the whole thing was going to be on full height retaining walls. Do you perhaps think that is going to look too urban?

 

The diagrams and pics in the book on pages 20-25 show how the end of the girder is supported on a bedstone (padstone) which might typically have a column below it. Sometimes there is then a decorative pillar on top of that, sometimes not. If the girders have attractive radiused ends, it is a shame to hide them.

 

How long are the Peco girders? They don't look significantly too short in your mock-up. With a further re-alignment of the lower track we may be able to reduce the skew angle and shorten the span a bit.

 

Note that you said earlier that setting the trackbed edges in Templot to 60mm gives the required 30mm clearance. This is only true for straight track. On curves you need to add on a bit more for vehicle overhangs at the centre and ends -- see the dummy vehicle in the video.

 

In practice we could probably use modellers licence to reduce the clearance a bit, especially where the gap between passing trains and the masonry won't be very visible.

 

regards,

 

Martin.

[martin_wynne]

p.s. Gordon,

 

Looking again at your plan, if it was mine I definitely would not want full height retaining walls. These would normally have a parapet wall along the top, hiding your trains.

 

I think half-height walls alongside the green tracks would look far more attractive, with an embankment slope above that up to the high level tracks. This gives a much more spacious open look, and you can see the trains. It seems a shame to hide all that thrashing valve gear behind a parapet wall?

 

Martin.

[gordon s]

Having now checked with my visible track plan, I realise you are quite right Martin, the tunnel entrance under ET shed is much further away than I thought, so a low wall will be much better.  One of the things I'm keen to do is pick up on some of the bits I liked in previous ET plans.

 

These tracks are of similar height and separation and the low wall worked well.

 

 

 

It's still quite hard to visualise specific areas until the track bed is down and fixed into place.  I'm fairly hopeful of getting more more done is this particular area over the weekend, so with any luck I'll have some better idea of how it will pan out once the track bed is in place.

 

I have no problem playing around with Wills or Peco products or even scratch building the plate girders.  It will do me good to try something new and after all, we're supposed to make things...

Edited January 22, 2016 by gordon s

[The Stationmaster]

Thanks Alan for your concern.  I'm really glad you guys flag up these things as I do have selective blindness every now and again.  Even more thanks to Ian for confirming what I was thinking.  The 32" radii curves are well hidden from view, so I can deal with that even though it meant dropping my 36" radius rule.  I have around 20 professionally built loco's with the rest of them RTR stock.  I'll need to check the kit built loco's but I feel they will be OK, whereas RTR won't be an issue.

 

If it really becomes a problem then I'm quite happy to hand build a few lengths of plain track and widen the gauge if necessary to cope with rigid long wheelbase chassis.

 

OK, back to the bridge....

 

Thanks again for your efforts Martin.  It all makes sense now.

 

Here's the overall board plan set on my wife's new rug that cost four C & L turnouts.  Those of you reading John's thread on C & L will get the joke....

 

DSCF7917.jpg

 

....and here's the detail based on Martin's realignment of the single track.

 

DSCF7916.jpg

 

I had to print it out full size to see what impact it has.  Now I can see the slightly asymmetric alignment of the single track, which doesn't give me a problem.  It all makes sense now, Martin.

 

Having spent the morning shuffling between keyboard and kitchen floor, I'm going off to the garage to knock up some ply bits and bobs to fabricate the bridge before cutting a new ply track bed.

 

I still have one question buzzing round my head though and that revolves around the transition between the bridge supports and the retaining walls.  If both of those are set at a slight angle, say leaning back 5 degrees, that will create a compound angle at the point where the bridge support and retaining wall meet.  Not a problem at all cutting that in a bit of ply, but I am curious how that would have been dealt with in full size using stone or brickwork.

 

Would there have been a pillar as I suggested earlier or would there be some other structure to accommodate the join?

The walls supporting the bridge structure are usually vertical Gordon

[Ray H]

The quality of the content in the two images (and many others earlier) in post 2589 are what has kept me glued to this thread since I first came upon it.

 

I can't wait to see what magic you'll achieve with the latest version of the layout.

[92220]

To be fair Gordon, it is a really nice rug.....

 

Iain

 

 

PS

Very much enjoying both your progress, and your navigation through the complexities, as always. I agree with PhilH about the bridge sides, but a man of your abilities can probably sort that in his sleep.

Edited January 22, 2016 by 92220

[hayfield]

To be fair Gordon, it is a really nice rug.....

 

Iain

 

 

PS

Very much enjoying both your progress, and your navigation through the complexities, as always. I agree with PhilH about the bridge sides, but a man of your abilities can probably sort that in his sleep.

 

But 4 C+L turnouts would be more useful     

[eldavo]

Dunno about 4 C&L turnouts but it's a laser cutters worth! Was that the trade? It would make building the bridge girders a doddle.

 

Cheers

Dave

[Brinkly]

Looks cracking Gordon. Very nice work.

 

Kind regards,

 

Nick.

[gordon s]

Thanks for all your kind comments guys. Much appreciated....

 

This has been one of those days. Measure twice and cut once has always been one of my mantra's, but today was measure twice cut six times...

 

Modern machinery is a wonderful time saver, but dear oh dear, you can cut stuff very quickly to the wrong dimension. My railway room is someway from my workshop, so I seem to have spent all day traipsing back and forth and up and down the stairs trying to correct something that should have been right in the first place....

 

So after many hours and much cussing and swearing, I've reached the point of being very close to abandoning this whole flying junction bit and returning back to my original plan. The problem is the acute crossing angle and providing clearance against the various solid structures that are needed to support a flying junction.

 

I've got the trackbed cut and after many trips back and forth to the workshop, I have something that is presentable, but as always, the devil is in the detail.

 

To increase the clearance on one of the pillars, I have had to 'swell' the track outline to move it slightly out and in doing so the radius is reducing all the time. I'm now down to 37" to provide some additional clearance and now need to find some solutions before I head back towards abandoning this 'nice to have' element of the design.

 

The angle of the crossing has always been of concern and in an ideal world it would be much higher than the 26 degrees this design requires.

 

Moving it back to increase the angle is not an option as my gut feel says the clearance won't be there to accommodate the 1:100 gradients requirements I have set myself.

 

On the plus side , the parts are in place and all appears well. Where I am stuck at the moment is the transition between retaining wall and plate girder.

 

Here are some pics...

 

 

The bridge all makes sense and I have ordered the plate girder sides from the US. Martin, I had to move out the track around this bottom pillar as it all seemed quite tight, so I moved it back around 10mm, which reduced the radius to around 37". It's OK, but i'm unsure what to do with the ends of the supporting walls. Would they be left square or planed off at an angle? This side is no problem as the angle is 116 degrees and reasonable. The other side is just 26 degrees, so needs a different treatment.

 

I know these walls aren't right, but they serve a purpose. Here's adding a pillar, but that brings it's own problems with clearance to the track and going below 30mm...

 

 

So back to the drawing board and Bridges for Modellers came to my rescue with Figure 77 on Page 62.

 

This shows the support pillars planed off at an angle and the wall continuing around the side. It could look something like this....

 

 

It will need a pillar of sorts, but that overcomes the clearance issue and is fine for the obtuse angle, but that won't work with the acute angle. My thoughts are to leave that one square or once squared off, continue the line around to the low retaining wall and then fill in the rest.

 

Right now a combination of detail finishing and tight radii to clear obstacles is pushing me back to my original plan of no flying junction and a tunnel between the two pairs of main lines.

 

There are so many visual advantages of continuing down this route, but the detail is hard to kill right now. I suspect I will look at it again tomorrow and it may well be completely different and easily resolved, but if you have any ideas how to deal with the brick/stone work in this area, please feel free to chip in....

Edited January 23, 2016 by gordon s

[PhilH]

Must be the cloudy cider I've been imbibing but why do the angled support walls ( the ones that go under the top track) have to be so thick. If you reduced them down to a minimum thickness wouldn't that give you the clearance you need?

Edited January 23, 2016 by PhilH

[gordon s]

The thickness of the walls doesn't actually impact anything as in reality they are only 12mm thick. The 2nd sheet of 12mm is simply a spacer block. The trackbed has to be 6mm thick hence the step in the walls. I'm using 6mm as the padstone section and then 6mm trackbed to bring it flush with the 12mm trackbed.

 

Moving it backwards or thinning it out will increase the span of the girders or reduce the overhang of the girders to an unrealistic level. At a push I could widen the span, but I've ordered three girder spans that are 254mm long from the US. Of course I could cancel that order and build my own, but it appeared an ideal solution.

 

The problem really is the shallow angle of 26 degrees as you end up with one obtuse wall and one quite acute wall, far too pointed to be made in brick unless the walls are chamfered back as in my prototype I hacked together yesterday.

 

The left hand side has to be a full height retaining wall as the spacing between the tracks in insufficient for a half height wall and grassy bank. That is a possibility on the right hand side, so I think I can deal with that.

 

I was surprised to see the pic in BFM's where the brickwork/stone walling continued around the angle with no pillar as such.

 

A few glasses of wine tonight and I'm sure the answer will fly out from somewhere....

Edited January 23, 2016 by gordon s

[martin_wynne]

Hi Gordon,

 

Have you settled on full height retaining walls then? Yesterday you seemed to be favouring open embankment slopes? In which case the abutment wall simply continues alongside the lower track, at a reducing height down to about half height. You don't need a corner or a column there.

 

Embankment sides are typically 1.5 horizontal to 1 vertical, so you can work out the drop of the top of the wall according to the space between the tracks.

 

If you follow the .box file which I posted you should have adequate clearance. You can cheat a bit on the clearance if you wanted to make panelled stonework between thicker buttresses.

 

regards,

 

Martin.

Edited January 23, 2016 by martin_wynne

[gordon s]

Thanks Martin.  Just taken a quick look whilst my dear lady is watching Casualty.  

 

That will work!  

 

No I'm happy with low retaining walls where there is the room to have a low wall and a reasonable incline between the two levels.

 

The left hand side is very tight as there is not an awful lot of space between the two sets of tracks at that point, so a full height wall will be necessary close to the bridge.  Referring back to the plan shows that the gap between those tracks widens out again, so a reducing wall would make sense once there is the space to accommodate it.  Taking the wall round the corner as it were, solves the clearance issue on that corner as well, so that all makes sense.

 

The right hand side of the opening is not an issue and whatever works on this side will work as a mirror image on the other side of the bridge.

 

It was a long day again today and after six hours of work and a heap of scrap bits, I had little to show for it.  I'm sure a good nights sleep will see me up for the challenge again tomorrow...

 

 

 

 

[jukebox]

Excuse the photoshop liberties Gordon, but something like this??

 

[martin_wynne]

...with added girder.

 

 

 

[skipepsi]

Looks like a winner to me but you could add a buttress if you wanted.

[martin_wynne]

Hi Gordon,

 

Using the dummy vehicle I have created a clearance line for the wall. .box file below.

 

gordon_new_bridge_2.box

 

This is the full official structure clearance (black line), you could infringe upon it a bit if necessary:

 

 

At its widest you have about 25ft width of embankment (100mm). So that means a drop about 17ft (68mm) down the slope, which is probably about 75% of the height difference. Which should look very effective with a low wall at the base of the embankment, rising in steps towards the bridge.

 

It does still require a slight change of direction at corner A. But to avoid that, you could continue the curve along the abutment under the girders, like this (black line):

 

 

A visiting civil engineer is then going to tell you that the middle girder is too long, but no-one else will notice. You could of course shorten it if you wished.

 

Strictly speaking it is more likely that the sloping wing wall would be straight rather than curved (pink line), to better support the embankment:

 

 

But a trawl through some books could probably contradict that.

 

regards,

 

Martin.

Edited January 24, 2016 by martin_wynne

[gordon s]

Many thanks for those Photoshop pics, guys, they look great!

 

I feel we've come full circle.  I have an inherent need to get things to flow in gentle curves, hence my question in post 2565 re the curvature of the wall.  To my mind it looked better, though there's no doubt it would probably have been frowned upon by the civil engineer, so I went for straight, which brought it's own set of problems in terms of angular corners etc.

 

This is all part of gaining experience so that next time a similar situation arises, you have a better understanding of the problems you may face further down the line.  I'm going to take a look at the curve implications, but it may involve grafting a new piece of shaped trackbed to the original trackbed which I cut with a straight edge yesterday.  

 

No big deal at all, we have the technology.....

 

Thanks for the .box file Martin.  I'll take a look at that after breakfast.

 

When I was building the last ET, I bought some 2mm MDF sheet which could be cut in a long strip  and curved around some supports to get a nice flow in and out of the bridge.  It may even be the top surface can be left straight thereby avoiding rework of the trackbed, with just the stone course taking the curve in and out.  If I had a preference I would always go for a curve, hence the total lack of straight track on ET.

 

I must admit the fabricated pics look so much better than I imagined and I'm convinced now on the merits of using the 7mm Slaters sheet.  It may not be to the correct scale, but it just looks right.  Getting a rule out shows blocks that are typically 4'6" x 1'3" or 4'6" x 2'6", so pretty large, but they seem to look so much better in large civil engineering locations.  The Wills sheet although to scale, still has the appearance on ornamental garden stone, fine in small areas, but it seems to lose a lot once used in substantial structures.

 

Not for now, but I've always laid my curved track flat and this time round I want to look at modelling the cant you see in every day.  The curve into the underbridge is crying out for cant and it will certainly add to the layout.  I suspect achieving that in double track will be a bit of a challenge, but I'm sure you guys will have some ideas.

 

Not now though, I have enough on my plate....

Edited January 24, 2016 by gordon s

[Siberian Snooper]

I like the idea of using the 7mm stonework for heavy civil engineering jobs. I have seen several layouts in 4mm that have used it too good effect.

 

For cant I have used a thin strip of 1mm thick card under the outside edge of cork underlay, where each track is canted seperately. For double track, under junctions etc. I put an extra strip under the outer edge, the cork seems to smooth out the step ok. It looks good too see a train lean into the curve. Don't forget to add speed restriction signs at junctions where there is adverse cant on the diverging road and the main road may also have a restiction too reduce the cant deficiency in the turnout road. Brent springs to mind where the down main had a restiction on 50 mph, can't remember what the branch was.

[gordon s]

Well it's taken a while and I have a little less hair than before, but I think we've cracked it.  Printed off a new set of sheets this morning with the revised line through the underbridge and tacked on some balsa strip to get the whole line through.  It maintains a minimum of 35mm clearance from the track centre line right through, with the most of the stone support walls still straight, so that will make it easier to build.

 

 

Sitting a rake of Mk1's on the paper track shows there is still a minimum of 12mm between the overhanging coach and the edge of the wall.

 

 

Once I've marked out the lines I'm going to push on and cut the ply to shape, so that's the end of this weeks episode.....

 

Thanks for all your input, once again...

 

 

 

[The Stationmaster]

Gordon I think cant would look nice in the visible area but as you have a reverse curve are you in danger with finishing up with twist in the single line just where you don't want it?