Dual Gauge Points - or Turnouts, if you prefer

[IrishPeter]

In one of those flashes of inspiration that gets one into BIG trouble - or at least a major project - I have been contemplating making the lower terminus of my layout dual gauge.  No - not Ga. O and Ga. 1, but Ga. 1 and Ga.3 (German - Spur II).  

Anyway, I would be thankful for some advice.

For a start, has anyone had a go at making dual gauge points of that size, and if so, what parts of the process had you reaching for something stronger than lemonade?  Secondly, any tips as to minimum radius?  I am thinking in terms of the Standard Gauge side as having nothing more drastic moving about than a 4-wheel shunter, and some typical 10' and 15' wheelbase vans, so I am thinking I could get away with 10' radius.

Thirdly, does anyone know of any templates?

Fourthly - you are permitted to call me nuts!

Cheers,
Peter in AZ

[andymctractor]

Fourthly - you are permitted to call me nuts!

You're nuts.
- but good luck.

We have Cliff Barker here in the UK who makes high quality track products. On on his Q+A page he answers a question 'What are the options for dual gauge track?' In his answer he briefly mentions G1/G3. Of course this is based on UK prototype equipment but you might find the website interesting.
http://www.cliffbarker.talktalk.net/Fre ... tions.html

Andy

[kandnwlr]

When I was doing the track for the K&NWLR, I decided in a fit of enthusiasm to design the lower loop in dual gauge 32 and 45mm including the points. After a long, long search I had them made by GRS, who offer a bespoke service. And they work, too.

More too, my hands don´t shake in the mornings after getting up. Well, no more than before.

[Tony Bird]

Hi Peter,

You might consider making one of these. This is a prototype of ones that have been in use on the CMES GR for three years. The ones used are made with plastic bases but look the same. They are G0 & G1 but could be made in G1 & G3. They can be made left or right hand straight or curved but not as a 'Y'. They have proved to work very well





Regards Tony.

[Soar Valley Light]

It might be best to go back to basics and design the geometry for yourself and your specific locations. Turnouts are not really that scary, the geometry is relativley simple, although making things dual gauge certainly adds a level of complexity that I've always managed to resist.

At the end of the day I wouldn't attempt anything without making a large scale drawing for something this complicated. I say large scale because most of my S&C design is for 12" to the foot scale - manufacturing errors are expensive in that scale! In fact, for model purposes the best thing is to draw it out full size and use the drawing as a template.

If you refer to some of the old 'standard' published works on more complicated S&C design the recomendation is exactly what I've suggested. This is specifically the case for three way or tandem turnouts where the geomterical considerations are not althogether dissimilar to dual gauge.

I would suggest that having an interest in geometry or S&C design (or preferrably both) is essential if you are going to embark on this, if not then whether or not you are nuts now will be immaterial - you will be by the time you've had enough of the project!

[IrishPeter]

Okay, this is going to sound dumb, but is S&C what I would call S&T?  If so, I have an interest, and a fairly strong one at that!  Geometry less so, but it is one branch of maths that I do NOT dislike with a passion.

I am currently poring over my old model railway manuals seeing how they made point when "Adam wor a lad!" Permanent Way for me is largely a matter of flat bottom rail and wooden sleepers, though so far this line has been laid with SVRR flexible track due to the local ant population.

Cheers,
Peter in AZ

[TonyW]

S&C = Switches and Crossings
S&T = Signals and Telegraphs

[IrishPeter]

OK, got it!  Thank you!  I never been around a railway big enough that Switches and Crossing had their own department.  I tend to geek out on S&T stuff - mainly the mechanical and "wind up" stuff - but I have been heard to say "that looks interesting..." when looking at a double slip, then the wheels start going round how it was made, so I stand a chance of getting through this.  

My usual favourite railway - the Isle of Man Railway - does not go in for complicated track layouts - everything is LH, RH, or Y, though some of it looks as though it was made to fit with a hammer, which is how I tend to go on with my model railway.  There is a cost factor there, just as there is in real life, and with Ga. 1 in the garden my space restraints are more imagined than real.

NG track work rarely seems to be complicated, though I did come across a double slip in the station throat of the old narrow gauge layout of the station at Kristiansand. Frankly looked out of place as there was plenty of room.  I suspect someone had decided that there might be problems reversing 15 or 16 metre NG stock over the diverging routes of back-to-back left handers, so they did the double slip to eliminate potential trouble. You also get some interesting track geometry on Indian Metre and 2'6" gauge, and of course, the Noggerbahn has its share of interesting point work around the Harbour station or, at least, used to.

Cheers,
+Peter in AZ

[Soar Valley Light]

Hi Peter,

It sounds to me like you stand a fair chance of achieving your aims here. You obviously have a 'feel' for track. Big complicated track layouts look good - but if you have to build or maintain one it's a different matter. I've often been heard to say that double slips look good in skips! With one exception I've managed to avoid using them in my track designs, full size and model. (The exception was a full size one!)

Only a couple of rules govern the absolute basics of turnout design. First and foremost the radius of the turnout is governed by a simple intersection between two lines. These are the crossing angle and it's intersection with a straight line from the switch heel. OK, it's already starting to sound complicated - trust me, it isn't. This is particularly the case in narrow gauge turnouts where the switch blades are often straight. This relationship also dictates the 'lead' of the turnout, that is the distance from the switch tip to the crossing nose. Once you have these two things (radius and lead) drawing out the turnout is simplicity itself (well, it helps if you have a set of railway curves!)

This is ok where we are dealing with turnouts to the left or right out of a straight main or through route. If the through route is on a radius though then the turnout radius has, by necessity and mathematics, to become tighter if the turnout is in the same direction as the curved main or slacker if the turnout is in the opposite direction to the curved main.

OK, I'll shut up now!!

[andymctractor]

Only a couple of rules govern the absolute basics of turnout design. First and foremost the radius of the turnout is governed by a simple intersection between two lines. These are the crossing angle and it's intersection with a straight line from the switch heel. OK, it's already starting to sound complicated - trust me, it isn't. This is particularly the case in narrow gauge turnouts where the switch blades are often straight. This relationship also dictates the 'lead' of the turnout, that is the distance from the switch tip to the crossing nose. Once you have these two things (radius and lead) drawing out the turnout is simplicity itself (well, it helps if you have a set of railway curves!)
This is ok where we are dealing with turnouts to the left or right out of a straight main or through route. If the through route is on a radius though then the turnout radius has, by necessity and mathematics, to become tighter if the turnout is in the same direction as the curved main or slacker if the turnout is in the opposite direction to the curved main.

OK, I'll shut up now!!

Am I so self satisfied to be reliant on Peco sm32 track and pointwork? Though it means 45mm gauge visitors to my line will have to be satisfied with just a cup of tea, plenty of chat and friendly abuse.

[IrishPeter]

Not to put too fine a point on it - it depends what you are trying to achieve, Andy.  The 32mm guys are a majority in the UK, and as 2'gauge was the commonest in the UK that is only to be expected.  Unfortunately, or fortunately, depending on your point of view, 2' gauge does not float my boat.  I prefer prototypes around 3' gauge, so for now I am a 45mm gauge man, and when I am talking dual gauge I am thinking of a third rail for Ga. 3, so I can run the odd standard gauge wagon around to hint at interchange with the mainline!  O gauge around here is the preserve of the .25" scale standard gauge guys.

Cheers,
Peter in AZ

[Soar Valley Light]

Hi Andy,

No, your not self satisfied at all. There is nothing wrong with buying in. In fact you are in very good company. Network Rail buy in all their S&C from the manufacturers and this initially comes in as complete, pre-assembled, units or layouts. This has been the case for many years, you have to go back quite a lot of years to find many companies building their own from components.

Each to his own and if purchasing off the shelf is the correct solution for you, then that's great. If a bespoke item of S&C is needed for a very specific location then it's a little more difficult in model form as it's has to be made by a specialist who will charge you more. (If you go to a standard gauge manufacturer the price for a standard turnout is the same whether it is 'out of straight'(right or left hand), 'symetrical' (a Y point), or bent double!

There are, of course, a few weirdos (of which I am one! ) who take delight in making our lives more complicated by faffing about wasting time building our own just because we can! As I've often said before, that's the beauty of this hobby, we each do as we please in all the various aspects of the pastime.

Andrew

[IrishPeter]

With track my usual motto is 'buy in everything you can' - it makes laying and relaying quicker and easier. I only consider scratch building when I need a custom item. I find this is a good way of ensuring that I remain somewhat sane, and that some of my projects get finished.

OTOH, being a bit of an operations nut, I do tend to design layouts with one odd or awkward feature to confuse visitors and occasionally myself. The present railway has a couple of awkward kick back sidings which require a little thought to be put into shunting. The upper terminus' goods shed is reached from the head shunt to the loco run round loop. That can make it a bit difficult to know where to put the passenger stock whilst shunting a mixed train. At the other end there is a quay siding which is approached in a similar manner.

Cheers,
Peter in AZ