Building/Using a test vehicle on hand built track

[gordon s]

It's a few years since I started building my own point work and I feel I have got to grips with it, but one thing continually puzzles me. When building I use an old brake van with wheels set at 14.4mm B2B to test the smooth running and this works fine, but once I start testing with locos, I invariably find I have to tweak the gap between the check rails and the outer rail to ease the gauge to accept different types of locos. I should stress I never change the check rail/crossing relationship as that is the critical part of any turnout. The gauge is actually less of an issue.

 

I'm sure after all these years I am building correctly and to spec, so am ruling out the track, rightly or wrongly. Typically I find diesel locos with their short wheelbase and small wheels pass through no problem, but then I do see tight spots with steam locos where the wheelbase is longer and the wheels themselves larger. I do wonder though if you tweak track for one type of loco, do you introduce a problem for another assuming all the B2B's are consistent.

 

My goal from the outset is to build turnouts where stock will run smoothly and without bumps at all and in most cases I manage that, but I'm never sure what type of vehicle to use as a test piece.

 

I have thought about buying an old scrap 9F off eBay and using that as a test vehicle, but will the additional easing give me problems in other areas?

 

How do you deal with this issue?

 

What do you use to test smooth running on crossings and check rails?

 

Going back to the rightly or wrongly question, is it a case that track built correctly will accept a wide range of wheel sizes and wheelbase lengths? That seems impossible to me, but I'm happy to be proven wrong.

 

Is easing the name of the game and normal?

[edcayton]

Do all the vehicles have wheels to the same standard? If that is the case then I think that you are stuck with the problem-unless you re-wheel the stock that doesn't run well.

 

Not my idea, but I have seen a test vehicle consisting of a sheet of perspex (or similar) mounted on two bogies, enabling you to see what is happening as the wheels go through the points. You could do this, but fit different spec. wheels on the two bogies.

 

You don't say what radii you are using, but that could also be a factor

 

Ed

[gordon s]

Thanks Ed. Bogie vehicles are not an issue as they have small wheels and a short wheelbase, so whilst helpful, it would not help eliminate the issue whilst building. I have an old 0-6-0 chassis I've tried and that improved things, but I am curious what others do.

 

All my turnouts are a minimum of 36" and I only have a few of those. Most others are 4' plus. I run a mix of new RTR, Markits and Ultrascales through 00-SF and there is no issue in the crossing itself or the wheel standard. As far as I can see the issue with wheels is more to do with diameter and the length of the wheelbase and not tyre width or flange depth.

 

The check rail length is set by Templot and I'm using 1mm shim to set the gaps for check and wing rails. All other critical measurements are as per gauge standards.

 

The tightness is only there with long wheelbase locos and steam locos in particular, so I'm guessing it is a binding issue caused by the length of the check rails and the length of the fixed wheelbase. My method of dealing with this is to slightly widen the overall gauge by moving the outer rail next to the check rail, leaving the check rail to crossing distance unchanged.

 

My question is what do other builders do to set up turnouts and what would they recommended as a test vehicle in the build process?

[34theletterbetweenB&D]

The best way is to maintain the track standard consistently correct for the wheel standard in use, and then make the vehicles conform. What you need for this is a template piece of track on the test bench representing the smallest curve on the layout (or in a range of smallest curves for as many route restrictions you intend to apply) on which basis you test and alter to conform as required.

 

How I should like to be a fly on the wall in the Hornby design office when they start waving a certain eight coupled tank loco chassis at the effective radius of their standard points...

[martin_wynne]

The check rail length is set by Templot and I'm using 1mm shim to set the gaps for check and wing rails.

 

Hi Gordon,

 

You must not use the 1.0mm crossing flangeway gauge shim to set the check rails -- it is for the wing rails ONLY.

 

Check rails should always be set with the 00-SF check gauge tool specifically provided for the purpose. If you are not sure which rails are called check rails and which are wing rails, here is a diagram:

 

 

The track gauge can be widened by whatever amount is needed for the radius and rolling-stock in use. When you widen the gauge, the flangeway gap at the check rail widens by the same amount. For turnouts sharper than about 3ft radius in 00-SF you may as well use 16.5mm roller gauges for the curved diverging road. For easier curves the gauge-widening provided by the 00-SF 3-point gauge should be sufficient, but only trial and error can decide this.

 

To test running you need a typical 6 or 8-wheel chassis, not 4-wheel, and the available sideplay on the middle axle(s) is significant. Just keep widening the gauge by whatever it takes until your longest stiffest wheelbase runs through, but make sure that the check rail gap widens by the same amount. The check gauge tool must fit the check rails in all cases.

 

If the test vehicle has wheel flanges thicker than 0.8mm it is probably not suitable for 00-SF. Measure the flange thickness by holding the wheel against a bit of rail and measuring across wheel and rail, then subtract the rail width.

 

The length of the check rail is not usually significant and is determined by the prototype, as shown on the templates.

 

regards,

 

Martin.

[gordon s]

Apologies Martin, let me rephrase what I do. I set the wing rails from the vee using the 1mm shim and then set the check rails with the check rail gauge supplied by Brian Tulley, so the wing rail and check rail are set correctly. Where I use the 1mm shim is to set the outer rails from the check rails. I always build in that order. Vee first, then the wing rails, then the check rails all of which are set using the correct gauges. Only once they are all in place, do I set the outer rails and then last of all the switch rails.

 

If I make any adjustment at all it is to the outer rails only by widening the gauge slightly to relieve and tight spots, hence the query on long wheelbase locos.

 

I was under the impression I was doing it correctly, perhaps I didn't explain it very well or used the wrong terminology.

 

With regard to a test vehicle, you have answered my question, so many thanks for that.

[martin_wynne]

Where I use the 1mm shim is to set the outer rails from the check rails.

 

Hi Gordon,

 

Oh I see. Yes that way round is ok, but if you simply say you use the shim on the check rails, most folks would think you meant using it to set them.

 

Using it your way will give you a tight 16.2mm track gauge, which is only strictly necessary in complex formations where wing and check rails merge. The specified track gauge dimension on prototype and model is always a minimum figure, and there is no harm in widening it a bit through plain crossings if it helps. Or even a lot on sharp curves.

 

The most important dimension is the check gauge. The other rails could just about be set by eye from the template, but not the check rails. You must use the proper check gauge tool for those.

 

The 00-SF check gauge tool is also correct for 00-BF and DOGA Intermediate, and as far as I know this critical gauge tool isn't available anywhere else. So modellers using those standards may wish to acquire a pair of the 00-SF tools for setting check rails.

 

regards,

 

Martin.

[gordon s]

Thanks Martin, that's a relief. At least you've confirmed what I was thinking.

 

I do have a 0-6-0 chassis fitted with Markits wheels to use as a test jig, but suspect a 9F would be similar once you allow for the flangeless centre drivers.

[hayfield]

Gordon

 

I may have got the wrong end of the stick but,If you are building to 00-SF standards it is my understanding that you should be using a 16.2 gauge to set the stock rails from the V, if you are building a curved turnout then you must use a 3 point gauge.

 

The check rail gauge is used to set the check rail, and I see that in princible the stock rail could be set by using a wing rail gauge but that opens up the possability of errors creeping in (using 2 gauges instead of 1. But then I could be wrong, I do understand that the placing of the check rail is more important than the stock rail.

 

I think the main problem being

a) vairable wheel back to backs of stock

B) wheel base not being flexable enough to go through sharp radii turnouts

[gordon s]

Thanks John. I'm happy it's not a B2B issue as these are all checked and set before running and none of my turnouts are less than 36" with most 48" plus.

 

Because of these large radii I've never had need to use a 3 point gauge, but I did used to build the way you suggest by gauging the outer stock rail from the vee. I stopped doing that deliberately as that was using two gauges and introduced problems, so preferred to set the outer rail from the check rail, once the check rail was set in it's correct position using the check rail gauge.

 

My understanding is that the actual track gauge is nowhere near as critical as the other dimensions, so I always ensure a minimum 1mm gap between check rail and outer rail using the 1mm shim. My turnout building has probably been too accurate as Martin suggests with the gauge set at 16.2mm at the check rail, whereas a little easing at that point would allow longer wheelbase locos to pass through easily. This is particularly relevant on kit built chassis where the side to side play is reduced compared to RTR chassis so your last point is probably the right one, albeit that 36" plus radius is not that sharp.

[gordon s]

Just a quick post of thanks guys, for all your input. I've made up a test mule from an old 0-6-0 chassis fitted with Markits wheels and axles. I've used washers to remove most of the side play so it will represent a much longer chassis in practice. Pleased to say a few minutes with the soldering iron and all the turnouts now take steam locos faultlessly. Just by moving the outer rail out in any tight spot by 0.2-0.5mm has made all the difference and removed the tendency for steam locos to derail as they negotiated the curve. That leaves the critical area of the wing rails and check rails untouched and perform as per spec.

 

Great forum with some very knowledgeable guys, but then we all knew that....

[Guest Natalie Graham]

One good tip is to use at least two vehicles to test the track, push one through with the other(s). That way you don't inadvertantly guide the test vehicle through the turnouts when pushing it by hand.

 

As an aside, when I was 15 I built a 10' x 2' 00 layout using soldered track and testing it with a Peco wonderful wagon. I chose this as it was my best running vehicle and I thought that any problems would be down to the track not the test vehicle. This was fine until I wired it all up and tried to run my Triang-Hornby locos and stock. None of them would go through any of the pointwork. I sold the lot and switched to N gauge after that.

[hayfield]

Thanks John. I'm happy it's not a B2B issue as these are all checked and set before running and none of my turnouts are less than 36" with most 48" plus.

 

Because of these large radii I've never had need to use a 3 point gauge, but I did used to build the way you suggest by gauging the outer stock rail from the vee. I stopped doing that deliberately as that was using two gauges and introduced problems, so preferred to set the outer rail from the check rail, once the check rail was set in it's correct position using the check rail gauge.

 

My understanding is that the actual track gauge is nowhere near as critical as the other dimensions, so I always ensure a minimum 1mm gap between check rail and outer rail using the 1mm shim. My turnout building has probably been too accurate as Martin suggests with the gauge set at 16.2mm at the check rail, whereas a little easing at that point would allow longer wheelbase locos to pass through easily. This is particularly relevant on kit built chassis where the side to side play is reduced compared to RTR chassis so your last point is probably the right one, albeit that 36" plus radius is not that sharp.

 

Gordon the best way to build turnouts is to use the method that suits you (providing its correct), and for finescale wheels your accuracy is spot on. The trouble lies with the manufactures being able to vary the B2B slightly and stay within 00 tolerances.

 

Regarding locos with rigid chassis having difficulties on the tighter radii, having the center wheel as the stiff one and the outer two being able to have a bit of side play could reduce the problem, problem arrises when either the frount or rear wheel is the driven wheel.

 

To test 00 turnouts, I use an old Mainline J72 (the only RTR loco I have that runs on code 75 rail) which has 2 different B2B on its drivers, I may be just lucky but this seems be spot on for both finescale and RTR wheeled locos as a gauge tester.

 

As you said ease the check-rail gap slightly solves the problem if RTR locos stick through the crossing. Building in EM is much easier due to the stricter tolerances.

 

Must say, I find others building methods both interesting and informative.