What's best for testing?

Discuss the prototype and how to model it.
garethashenden
Posts: 270
Joined: Tue Apr 07, 2015 9:41 pm

What's best for testing?

Postby garethashenden » Wed Jul 26, 2017 5:49 pm

I've now reached my least favorite stage of track building, fitting point blades and TOUs, and I'm wondering what's best to use to test their operation? The layout will mainly (exclusively?) see small 4 wheel wagons, so I've used a few of those, but I'm wondering if I should be using something else as well. Do I need to find something with bogies for a more complete test? What's the general advice for testing new track?

David Knight
Posts: 620
Joined: Sun Jul 20, 2008 6:02 pm

Re: What's best for testing?

Postby David Knight » Wed Jul 26, 2017 6:37 pm

Gareth,

I test the track with the longest wheelbase locomotive that is likely to be used on that section of track. My reasoning being that if it will take the big one, the rest should follow.

Cheers,

David

User avatar
Tim V
Posts: 2204
Joined: Tue Jul 29, 2008 4:40 pm

Re: What's best for testing?

Postby Tim V » Wed Jul 26, 2017 7:41 pm

Longest rake you can assemble, propelling and pulling with a locomotive.

Anything less is wasting your time.
Tim V

User avatar
Allan Goodwillie
Posts: 710
Joined: Sun Jul 20, 2008 7:00 pm

Re: What's best for testing?

Postby Allan Goodwillie » Wed Jul 26, 2017 9:19 pm

Hi Gareth, :) :)

If you have a look at the following https://www.scalefour.org/forum/viewtopic.php?f=39&p=54421#p54421 which is a post covering a course I am running for my group of "Starter" friends.

You will discover that I start testing while the point is being constructed using a long wheelbase wagon or van which is uncompensated and which has had the wheels checked for the correct BtoB and true running on a sheet of glass. I start before any check rails are fitted as the wagon should go cleanly through the crossing V without any sign of catching. Listen as you run the wagon through to hear any slight click. There should be no sound. I also show how to set the point blades temporally to evaluate the running quality. If all is OK on the track making jig then the check rails are fitted and the point further tested.

Once laid I do the same as Tim and David, again I check all the vehicles in the train first - I have a train load of 2 ounce uncompensated hopper wagons again all checked - including buffer height which I use as well as the longest wheelbase 0-6-0 I happen to have. Looking for smooth running I run the trainload back and forward at increasing speed until something happens.

If the point is fine then you should be able to run trains without any wagons coming off at scale speeds.

If the point is properly tested during the construction period then it likely that if there is a problem after laying then it is probably due to one or two of a number of things.

1) The point is not level and therefore there is a twist - there is a little gadget you can make to check for this - if you want to make one I could show you. It requires a couple of wagon compensating units and some brass wire. The twist could have come about due to an uneven surface - holes drilled through cork and not properly sanded down for example or a rivet not properly closed up properly below the sleeper.

2) If the point is an interlaced one it is possible to have distorted it between the making and the fitting - it may have gone out of gauge - I use a number of gauges to check during the fitting and do not assume that it will remain as it was on the jig.

3) The point blades are not correctly set when fitted to actuator. Correct gap? Correct height? Enough throw? - a number of possibilities.

4) Chairs or solder in the wrong place catching on flanges if fitted or parts soldered after laying. - filing down may be necessary. - I had an interesting example of this when a small 0-4-0ST loco I had built and which operated well on Dubbieside, but when I tried running it on the first section of Burntisland it kept cutting out - it happened that the wheelbase was the same as between pairs of chairs which had been fitted cosmetically and which were too high - lifting off the flanges of the locomotive!

5) There may be other possible reasons for incorrect operation of points - there is discussion elsewhere on the forum about problems arising from the incorrect use of gauges.

I have not covered laying and fitting out points yet on the thread, but hope to do this when we meet again after the summer.

Hope that is of some help. :)

User avatar
Guy Rixon
Posts: 580
Joined: Sun Mar 27, 2011 6:40 pm

Re: What's best for testing?

Postby Guy Rixon » Thu Jul 27, 2017 8:07 am

(In addition to the excellent suggestions above:) Run the longest-wheelbase non-bogie stock that you have, as it will be most sensitive to track twist. If you have nothing with a long wheelbase, perhaps borrow some stock to test with? Six-wheeled coaches would be good test-vehicles. Bogie vehicles are supposed to be more tolerant of track twist.

User avatar
Will L
Posts: 1623
Joined: Sun Jul 20, 2008 3:54 pm

Re: What's best for testing?

Postby Will L » Thu Jul 27, 2017 1:36 pm

Guy Rixon wrote:(In addition to the excellent suggestions above:) Run the longest-wheelbase non-bogie stock that you have, as it will be most sensitive to track twist. If you have nothing with a long wheelbase, perhaps borrow some stock to test with? Six-wheeled coaches would be good test-vehicles. Bogie vehicles are supposed to be more tolerant of track twist.


I'd go with your coaches too. They will be the longest wheel base vehicles you have, and if the bogies are attached too rigidly can also be very sensitive to track twist. Lesson learned years ago when the club I belonged too built a curve with super-elevation. Everything except the coaches went round it fine. The coaches came strait off.

User avatar
David Thorpe
Posts: 806
Joined: Tue Oct 21, 2008 11:13 pm

Re: What's best for testing?

Postby David Thorpe » Thu Jul 27, 2017 5:10 pm

Will L wrote:I'd go with your coaches too. They will be the longest wheel base vehicles you have, and if the bogies are attached too rigidly can also be very sensitive to track twist.


Quite. My newly laid points were working fine until I ran a rake of coaches over them and half of them derailed. Entirely my fault - it turned out i hadn't laid the points flat and there was a slight twist in them. That didn't show up with short wheelbase stock. But this really applies more to how you lay your points rather than how you build them.

DT

garethashenden
Posts: 270
Joined: Tue Apr 07, 2015 9:41 pm

Re: What's best for testing?

Postby garethashenden » Thu Jul 27, 2017 5:38 pm

Thanks everyone, this has been really helpful. I'll try to use a variety of stock. In addition to "normal" wagons, I've got a LNWR D14 which has a 16' wheelbase. That's the longest rigid wheelbase I've got. After that I have a Bachmann Crocodile with P4 wheels, which did fine a fault that has now been fixed.

It seems I need to get some more stock, long coaches and pacifics...

Terry Bendall
Posts: 1597
Joined: Sun Jul 27, 2008 7:46 am

Re: What's best for testing?

Postby Terry Bendall » Sun Jul 30, 2017 8:30 am

A piece of clear acrylic (Perspex) about the length of a four wheel wagon with wheels mounted in fixed compensation units is good since you can look through the acrylic and see where the wheels may be coming off.

Terry Bendall

User avatar
Allan Goodwillie
Posts: 710
Joined: Sun Jul 20, 2008 7:00 pm

Re: What's best for testing?

Postby Allan Goodwillie » Sun Jul 30, 2017 8:42 am

:) That's one which I have seen before somewhere Terry - I might make one up for using on my own new layout with a couple of adaptions for showing twists and changes in elevation. Old grey matter churning around now! I hope to be ready to start on making and laying track by the end of this next week. ;) Working on the baseboard ends today.

Terry Bendall
Posts: 1597
Joined: Sun Jul 27, 2008 7:46 am

Re: What's best for testing?

Postby Terry Bendall » Mon Jul 31, 2017 6:27 am

Allan Goodwillie wrote:That's one which I have seen before somewhere Terry


Although not my idea Allan. My good friend Barry Luck uses the idea and I seem to recall seeing it elsewhere as well

Terry Bendall

User avatar
Noel
Posts: 1049
Joined: Wed Jun 23, 2010 1:04 pm

Re: What's best for testing?

Postby Noel » Mon Jul 31, 2017 11:53 am

Terry Bendall wrote:Although not my idea Allan. My good friend Barry Luck uses the idea and I seem to recall seeing it elsewhere as well


No acrylic, but wires attached to the compensation units to make the relative movements clearer, perhaps? MRJ 57 page 230.
Regards
Noel

User avatar
Allan Goodwillie
Posts: 710
Joined: Sun Jul 20, 2008 7:00 pm

Re: What's best for testing?

Postby Allan Goodwillie » Tue Aug 01, 2017 1:03 pm

Well done Noel, :)

I knew I had seen it somewhere before and made a version for myself,clearly it shows that Dave Reynolds had come up with the useful idea and made it for a 10ft wheel base. I would recommend a longer wheelbase myself, but a very useful tool. I also have a Don Rowland diplometer to gauge just what is happening when building cant into the railway.

Thinking I might add all features together to make up a new unit which could be built to allow both multiple wheelbases and uncompensated as well as compensated. I have a lot on this week - so possibly next week. Dave Reynolds had made his as he was hoping to build a layout that basically did not need wagons to be compensated. I wonder how he managed to get on with his project. :?:

User avatar
Flymo748
Posts: 2160
Joined: Sun Jul 20, 2008 6:00 pm

Re: What's best for testing?

Postby Flymo748 » Sat Aug 05, 2017 9:51 pm

Another alternative is the Masokits Track Defect Detector...

Masokits Track Defect Detector.JPG


I've had this etch for a couple of years and really must get around to building it. However it's having the pre-planning to order a pair of Exactoscale wagon wheels to go into it which is probably the main constraint. I look at an eight month waiting time, and wonder if I really can be bothered!

Cheers
Flymo
Beware of Trains - occasional modelling in progress!
www.5522models.co.uk

User avatar
Flymo748
Posts: 2160
Joined: Sun Jul 20, 2008 6:00 pm

Re: What's best for testing?

Postby Flymo748 » Sat Aug 05, 2017 10:04 pm

Terry Bendall wrote:A piece of clear acrylic (Perspex) about the length of a four wheel wagon with wheels mounted in fixed compensation units is good since you can look through the acrylic and see where the wheels may be coming off.


I've had three perspex floored wagons as part of the kit which I take on the Society Stand for demonstrations for a couple of years. I'm sure a fair number of people here have seen them over that time.

The idea is to show those who are not familiar with the concepts of springing, compensation, and rigid suspension in an easy way. As has been mentioned, you can push them along and see the movement of the wheels on the rails and through crossings.

Perspex wagons.JPG


The perspex is about 5mm thick. I bought a 12" square for not-very-much-money from Ebay and scored and snapped it to size. It's a bit of a sod to drill and screw into though. To make the wagon effective as a test vehicle, you have to have the axles *exactly* square in all aspects. I did this by drilling holes through and using screws which were a fractionally loose fit, so could be aligned and then tightened up when the alignment is correct.

Perspex rigid.JPG


I hope this gives people some ideas on how this can be done. I've certainly found it a useful gadget to have around.

Cheers
Flymo
Beware of Trains - occasional modelling in progress!
www.5522models.co.uk

Terry Bendall
Posts: 1597
Joined: Sun Jul 27, 2008 7:46 am

Re: What's best for testing?

Postby Terry Bendall » Sun Aug 06, 2017 8:07 am

Flymo748 wrote:The perspex is about 5mm thick. I bought a 12" square for not-very-much-money from Ebay


Some the larger suppliers of glass also sell acrylic which is where I got my "offcut" Having bought some acrylic for another job I asked if they had any small offcuts. Out came a piece 6ft x 1 ft which will do all that I need and more for the price of a donation in the charity box on the counter.

Terry Bendall


Return to “Track and Turnouts”

Who is online

Users browsing this forum: No registered users and 2 guests