A traverser

[burgundy]

I am beginning to pipe dream about life after Roswell Mill and a layout that could handle 20 wagon coal trains (UK, pre-grouping for the avoidance of doubt!). Just doing the arithmetic, I reckon that a loco and brake van accounts for about 12 inches and 20 wagons, @ each 3", makes a total of 6 foot. To optimise space and minimise turnouts, I have been thinking about a traverser, as the best way to provide fiddle yard capacity, with trains able to enter from either end. It would not need to rotate but merely hold 5 or 6 parallel roads with single track entry and exit. 

Can anyone advise please

- are there any major downsides to this sort of arrangement?  

- is 6 foot long too big to manage in a traverser?

- does anyone produce laser cut traversers that would do the job?

- are there any short cuts that would save me from having to re-invent it all for myself? Plagiarism is so much easier than original thought!

Best wishes 

Eric 

 

[teaky]

1 hour ago, burgundy said:

I am beginning to pipe dream about life after Roswell Mill and a layout that could handle 20 wagon coal trains (UK, pre-grouping for the avoidance of doubt!). Just doing the arithmetic, I reckon that a loco and brake van accounts for about 12 inches and 20 wagons, @ each 3", makes a total of 6 foot. To optimise space and minimise turnouts, I have been thinking about a traverser, as the best way to provide fiddle yard capacity, with trains able to enter from either end. It would not need to rotate but merely hold 5 or 6 parallel roads with single track entry and exit. 

Can anyone advise please

     You might want to double check your assumptions on train lengths to ensure you account for wagon spacing with couplings at full stretch and the longest locomotive you're likely to run plus a little space at each end just to make train parking easier.  (I've been using 85mm for wagons, 100mm for brake vans and 300mm for locomotives.  This would add an extra foot over your calcs.)

- are there any major downsides to this sort of arrangement?

     I can only think that it takes a little longer to retrieve trains from storage that it does using a fiddle yard with points.

- is 6 foot long too big to manage in a traverser?

     I have no experience of building a traverser but I will have soon.  I am planning a larger one, so I hope size isn't an issue. 

- does anyone produce laser cut traversers that would do the job?

     https://www.graingeandhodder.co.uk/store/c3/Traversers.html

     There is also Tim Horn and White Rose but you'll need to ask them for details.  There are probably more.

- are there any short cuts that would save me from having to re-invent it all for myself? Plagiarism is so much easier than original thought!

     Have to tried searching RMweb? 

Best wishes 

Eric 

 

 

[DCB]

The Train lengths are too short by quite a margin by modern Post WW2 standards but should be OK for pre 1923 based on 10 foot wheelbase wagons rather than the 12 footers normally found RTR.  I allow 3 and 1/2 wagons / foot.  Many pre group locos were also shorter generally though those 0-8-0s were long beasts.

That said Traversers are a good way to save length at the expense of width,  a 6 road single entry road traverser will be almost 2 feet wide  from full left to full right, a six road yard with points approach just over 1 foot wide. The points approach would be around 2 feet 6" long based on Peco streamline 2ft radius.  Most traversers are much shorter than your 6 feet, are single ended, sit on flat table, have few pieces of stock on them and still jam.   6 feet long will need a substantial base and some form of wheels, ball bearings? so it slides freely and guides. rails? so it sides accurately and doesn't jam, on the plus side 6ft timbers are readily available (as are 8 foot) so a nice strong traversing deck shouldn't be too difficult nor should a good solid base for it to slide on.   It will need a lot of skill to get everything to line up and work reliably and consistently but it sounds like a good idea.   Motorising it so both ends are powered might help stop it from jamming.

What a traverser is not much good at is for remarshalling trains. 

[gordon s]

Around 11 years ago, I built a large traverser for my own layout. Overall it had to be big enough to take 8 coach trains plus a loco, which equates to something like 24 wagons. The overall size was 2800mm x 750mm and it had 16 tracks across.

 

The problems I found were all related to alignment and the overall weight of the unit when extended. Even with four heavy duty runners, track alignment in all planes was an issue. Originally I thought I could have one access track, but when fully extended the weight of the bed would actually tip the track bed and pull the track out of alignment. That was easily solved by having multiple entry points to reduce the fore and after movement to a minimum. I am going to build another one, but this one will have three entry points and the max distance back and forth will only be 200mm with twelve tracks not sixteen. I would also build the support framework wider than the bed itself, so that it always remained within the bed structure and didn't overhang.

 

Having such a long bed, also meant it was possible for the corners to bind, if the bed wasn't pulled out perfectly straight. That was probably down to the alignment and fixing of the runners and here I have some ideas for my next one. Fully loaded the weight would have been considerable, so don't underestimate the free running quality of runners to support that weight. If it sticks, you could find stock off the rails with a sudden jerk as it frees.

 

If it helps, here are some pics showing the construction and nearly finished article.

 

 

Edited February 8, 2020 by gordon s
Pic duplication

[burgundy]

Thanks for all the suggestions that have been offered.

First, the moment of panic when I thought that I had underestimated the likely length (although 6 foot as a ball park is probably large enough to flush out the likely problems). I immediately went back and remeasured the stock for the proposed 20 wagon coal train - 1870s style. Stroudley C class 0-6-0 is a little less than 8", a brake van is a little less than 4" and a coal wagon is about 3" over dumb buffers (so 20 wagons equals 60 inches). I accept that this does not allow for coupling slack or a second brake van. Worst case, it might end up as a 19 wagon coal train! Passenger trains (of mainly 4 wheeled stock) will be rather shorter and I am thinking of stabling two of these in one of the 6 foot roads. A mainline express loco (2-2-2 or 2-4-0) is about 8" and a 4 wheel carriage is a bit under 5". 

Thanks to David and Gordon for confirming my first thought that a traverser of that sort of length is going to need pretty solid construction to avoid twisting and poor balance. I think I can manage with 6 roads on the traverser, which leaves a 5 road overhang either side, if I use a single entry/exit. I had not thought about more than one entry/exit road but it is certainly worth considering.

Since none of the baseboard manufacturers seem to offer a traverser as a standard item on their website - certainly not of these dimensions - I think I am back to building it myself. There are a couple of websites that offer pretty Gucchi hardware for this sort of purpose and I may have to explore this further.          

https://stationroadbaseboards.co.uk/cart_runners.htm

https://www.dccinterface.com/product/model-railway-premium-dcc-traverser-kit/

I shall look forward to following Gordon's progress if he builds a new traverser!

Best wishes 

Eric 

[Dungrange]

1 hour ago, burgundy said:

Since none of the baseboard manufacturers seem to offer a traverser as a standard item on their website - certainly not of these dimensions - I think I am back to building it myself.

 

Although the Grainge and Hodder traversers that Teaky highlighted are not six foot long, there doesn't seem to be any reason why you couldn't combine either two 900 mm traversers or a 900 mm and 1200 mm example.  What you would need to add would be some form of u shaped channel over the two edges of the traverser decks to ensure that both traversers move at the same time.

[burgundy]

43 minutes ago, Dungrange said:

 

Although the Grainge and Hodder traversers that Teaky highlighted are not six foot long, there doesn't seem to be any reason why you couldn't combine either two 900 mm traversers or a 900 mm and 1200 mm example.  What you would need to add would be some form of u shaped channel over the two edges of the traverser decks to ensure that both traversers move at the same time.

If I get the idea correctly, you would have to rig together two traverser units end to end. One of the issues identified in the comments above is the need to ensure rigidity, so that the traverser does not skew and get jammed. I am not sure that I can see how to achieve this with two units joined together. 

I guess that the approach would be to get Grange and Hodder to bespoke design a longer unit from the outset.

Best wishes

Eric 

[Harlequin]

Hi Eric,

You would save yourself a lot of trouble if you could avoid a traverser so it might be worth re-assessing that decision.

If you only need 6 roads then the points fans at either end wouldn’t be huge. Maybe there’s a way to fit them in somehow by stealing some space from other parts of the layout and/or using the end curves?

 

[Dungrange]

12 hours ago, burgundy said:

If I get the idea correctly, you would have to rig together two traverser units end to end. One of the issues identified in the comments above is the need to ensure rigidity, so that the traverser does not skew and get jammed. I am not sure that I can see how to achieve this with two units joined together. 

I guess that the approach would be to get Grange and Hodder to bespoke design a longer unit from the outset.

Best wishes

Eric 

 

Effectively a traverser is just like a drawer.  The Station Road Baseboards link in your post above is to nothing more than sets of drawer runners.  The issue is that the wider you make a drawer, or the longer you make a traverser, the greater the likelihood of the traverser skewing between the two sets of runners.  The closer you are able to place the runners, the easier it should be for both of these to move together and I suspect that is why the default lengths on the Grainge and Hodder website are 600 mm, 900 mm and 1,200 mm.  A bespoke longer unit won't necessarily solve the problem - it's more likely to make it worse.

 

What Gordon created in the photograph above is effectively two 1.4 metre long traversers joined together end to end - ie two sets of two drawer runners.  The problem is of course that since it was designed for eight coach trains these are perhaps still longer than desirable and perhaps it would have been better to have had three three-foot traversers joined end to end (ie using an extra couple of drawer runners).  Weight is of course the other issue and drawer runners are sold for different weights of drawer and contents.  However 16 locomotives and 128 coaches will weigh quite a lot and is perhaps getting up to the capacity of the drawer runners used.

 

If you were to purchase two of the Grainge and Hodder traversers, then I would assume these should each on their own operate smoothly.  The issue is making sure that both of them operate at the same time, which would mean adding something to what is provided in the kit.  That could be a timber of metal bar fixed along each edge (as long as it doesn't drop below the height of the frame) or something rigid that fits over the top of the edge pieces (provided it's not too thick or you'll reduce the width of the traverser).  I think that is the approach that I would take, but then my layout doesn't need a traverser and my previous plan, which did, isn't being built.

[DCB]

A traverser does not have to be like a drawer.  To work reliably a traverser should slide on a solid base.  Most, well all ,of  the exhibition layouts I have seen have their traversers sliding on a solid baseboard the full width of the traverser deck's travel.   If you cantilever the deck out then inevitably it will try to tip.   I designed a "Hockey Stick" traverser which is very space effective, but very odd ball, but forgetting that, if you want a wide traverser why not mount it on a trolley.  Just take the weight straight down onto some concentric wheels onto the floor.  Or just have outrigger wheels to take the weight of the overhanging section of the deck. Or even a folding outrigger baseboard section to support it?  

[burgundy]

On 09/02/2020 at 04:10, Harlequin said:

Hi Eric,

You would save yourself a lot of trouble if you could avoid a traverser so it might be worth re-assessing that decision.

If you only need 6 roads then the points fans at either end wouldn’t be huge. Maybe there’s a way to fit them in somehow by stealing some space from other parts of the layout and/or using the end curves?

 

Thank you Harlequin

I have been pondering this one over the weekend. The room is 13' long and the minimum radius will be 2' 6", so that the available straight section will be 8' at the theoretical maximum (i.e. track hard up against the end walls). To get a fan of 6 roads, the shortest pointwork would be a Y, followed by two 3 ways, which would add about 2' at each end. Some careful work on Templot should allow this to be condensed a bit, including moving the first turnout back onto the curve.

I guess that this just might work, so it is worth bearing in mind as an option.

Best wishes 

Eric