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from a 3.5 inch Gezina to 5 inch tramway Plettenberg locomotive

a conversion from a narrow gauge to tramway locomotive

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duncan webster07/05/2019 09:43:02
2198 forum posts
32 photos

Unlike a meeting of an average UK club, the majority of the drivers in Werner's video seem to be younger. What's the secret?

Must say that Werner's loco has got me interested in rehashing the Tich I started nearly 50 years ago as a tram engine. It's been 'finished' several times, but you can always do better. Haven't touched it for probably 35 years, but I think I know where it is!

Werner Schleidt07/05/2019 19:51:22
76 forum posts
125 photos

Hallo Kerrin,Duncan,

The Plettenberg runs very good .She is able to haul two adult persons. On our narrow curve with 6 m radius there is some wheel slip, but for a loco with 28 kg it performs very good. I am impressed that the small boiler have no problems to hold the pressure during driving. The only thing is to carefully look to the water level ,because the water came then out of the chimney. With some experience it is all manageable. The number 2 injector is a good fit and runs perfect. I found a mistake in the donkey pump. I got this with other valves and stuff by chance for a good price. At higher pressure as 3 bars there was only less flow. The comercial who build this has a teflon piston on the water side with a bad fit. I added an o ring and now there is much flow under pressure.

That is all fine tunning. I think it was a great idea to work with the 3,5 inch parts and build a new 5 inch chassis.

Duncan to your first question. The young guys are in the age of 14 and above. They are from familys where the father love trains . The youngster with the BR 24 at the beginning pulls his father to the trains. Now the are both in love with trains.

This was not an open day with public so all could go in a relaxed way. The BR 24 had his first succesfull run. I show the youngster and his father how to adjust the walscherts motion control. Before they can only drive forward. I show him the principle how to adjust the motion control . And with a little luck then it was perfect running. They bought this loco and it does not run under steam before.

Since the new managing comittee is working,I am a member of it , we try to transfer experience in a firendly way.

So the youngsters find physics very usefull and they have a lot of fun with gaining more experience. And this is nice to see. And they are better in school . One of them searched a job for practical training. He was one of hundred . As he told the personal boss what he do as his hobby, he was selected and he was very proud to learn mechanical things.

We have in the club special locos for the youngsters, but we let them also drive club trains under the control of an adult person. So they are proud to do this. And this starts the fire in them for the hobby.

But it is difficult to get offspring. You have to pull the father with them. And this is very difficult. There are so many other possibilities to do without getting dirt at the finger.

I think Tich parts are good to convert,too. Give it a start and it is a good winter project. smiley


Werner Schleidt25/06/2019 17:59:00
76 forum posts
125 photos

Hello all,

I had some work on a hot day with more than 30°C. Since some time agao I worked on a mesurement test equipment and the unpainted Plettenberg is a good test object.

I wanted to measure the pressure in the cylinder and the displacement of the piston. I want to see how this diagram is compareable to pubished charts in books. And in next steps the measurement of indicated power in relation to the force on the draw-hook and the driving speed will follow.

Today it was a little bit tricky , because I had jobs for 3 persons but I have to done it by my own. My Laptop and my camera had heat problems. It was good to have a back up.


The pressure sensor with adaptors.


The cylinder cover where it was connected.


Now installed.


The selfmade displacement sensor.


The time diagram green is pressure, red ist piston travel. From start to driving a few meters.

indikator 1.jpg

The full piston travel during start.


Starting and driving with closing of the steam valve to slow down a little bit.


Start and driving as above in xy diagramm


Werner Schleidt25/06/2019 18:14:15
76 forum posts
125 photos

Hello all,

I made a documentation video of my tests.

Werner Schleidt01/07/2019 11:05:03
76 forum posts
125 photos

Hello all,

I want to update some findings.

I looked in the theortical steam diagrams and so I had some doubts about my measurements.

I double check the electronic and all was correct. The doubt came up ,because the pressure at the beginning have to be high and then a steady phase and then To the end lower pressure.

In my measurements it is more in the opposit direction. So I asked me where this come from. The only involved part is the exentric. I measured the excentric and compared it to the 3,5 inch Gezina drawing. I saw there is an error in the dimension. It have to be 19.5 mm and it was 18 mm. I looked more into the system and had the opinion that 21 mm are correct. So I made new excentrics with 21 mm.

Than I test the loco with pressured air. In the first step the steam engine runs in forward direction much smoother than before . Backwards it was not so good but better as before.

I decided then to measure with pressured air to see how it changes.

indikator nh vw voll.jpg

this looks now more as a "Zeunert" Diagram . The pressure comes from the beginning some steady phase and a pressure drop to the end.

The steam engine runs smooth under this condition. With the reverse lever one step to the middle position it looks like the following picture.

indikator nh vw ez.jpg

The engine runs faster with less air usage, so the pressure increased a little bit,but the engine runs not so smooth as before.

In backwards direction the engine behaviour is not so good. The pressure increased to the end of the travel and the timming is not correct.

indikator nh rw voll.jpg

But it is better as before the change.

indikator nh rw ez.jpg

With the reverse lever to the middle position there was some compression to the end of travel. The engine behaviour is not so smooth as forward.

After the mesurements I change the position of the exentric a little and the behaviour was then better.

In the next days I will make a test run under steam to see how comparable is the experience with air to steam.

With steam it have to be much better. But if the principle adjustment with air is the same as with steam it is more easy to do and to measure.


Werner Schleidt04/07/2019 20:00:40
76 forum posts
125 photos

Hello all,

I made now the tests with steam. Steam tests are more complicated with my one man show. Where I have 3 jobs locomotive driver, video guy and measuring man.

In the measuring files I saw that the mesurement have to collect with dry steam and warm cylinders .Otherwise there are some peaks in the pressure measurements. You can see that in the pressure displacement curves over time. With warm cylinders the steam measurements are comparable to the air pressure diagrams. With this small model with wet steam and small pressure is this my finding.

With super heating and high pressure it is different I think. The next thing is ,the small model have no intensiv cut off in the steering.







My conclusion is to set the link motion and to control it it is Ok to do it air pressure this makes it more comfortable. I all is in good condition a steam test make sense. and doing all alone on a small track is not advisable. The test have tob done with more load.

In the video I found a mistake the last diagram was made with steam not with air.

I made a short video of all .


Over the winter I have to look if I can speed up my measurement system to a higher data rate. The rate of 96 measurements per second is Ok ,but multiplied by 2 ore 3 is better. But at the time now it is difficult to handle the amount of data. It is advisable to think about a procedure for the work.

I hope you can enjoy my work


Edited By Werner Schleidt on 04/07/2019 20:07:21

Neil Wyatt04/07/2019 21:01:34
16423 forum posts
685 photos
74 articles

Thanks for posting that Werner, it's interesting reading.


Harry Wilkes04/07/2019 21:35:07
699 forum posts
59 photos

Interesting video and engine


Werner Schleidt05/07/2019 12:58:44
76 forum posts
125 photos

Hello all ,

I think the knowledge base how indicator diagrams look like in the model range is small. The diagrams of big locomotives are more common.

I found these diagrams in a 100 years old thesis.

Tis one is more like the pulications I know .

It is from a Ball type engine

ithessist ball.jpg

And this one from a robinson engine.

ithessist robinson.jpg

The robinson type looks more like my model engine.

It will be interesting to have a knowledge base and more than the loco runs good.


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