Using a cheap circuit tester

Hi Peter.  It looks like the AC Voltage range is at the bottom.

If you use the 50 Volt position, you should get a reading on your needle.

The second row of numbers reads 0 - 50, Peter.

The graduations for individual Volts is in red.

Hello Peter

The circuit you have is called an Analog meter and relies on movement of the needle from 0 on the left and Full Scale Deflection on the right hand side for maximum voltage and current.  

The top line on your scale is the resistance line expressed in Ohms which is in reverse to the other scales but if you will, it is showing that a full electrical current will flow through  a wire. Before using this scale you should make sure that there is no power. You said you have used it for a continuity tester so I assume there is not much need to go much further than that except to say that you would be seeing a flow through your wiring when the Ohm meter scale is read…  

The small mirror which runs the length of the scale is so that you can align it visually and read exactly the voltage when you can only see one needle line instead of two through being out of parallax view.

The small screw head at the top is to adjust the Full Scale deflection to read zero when you just touch the two prods. You hold the two prods together then turn the screw till the meter does read right on the zero line which takes care of the life of the battery/ies inside the meter.
To check the voltage is easy. Firstly set your dial to the highest AC voltage (ACV) or DC Voltage(DCV) that you think you are likely to be using so as Max said 50 Volts. 

The next three scales reading down in order are 250V 50V and 10V.  Say the meter is showing the needle on 150 mark then depending on the scale on the selection dial, you are using you will have either 150V, 30 V or  6 volts. 

If it is reading 3 of the small markings beyond this marker, then you would be seeing  165V (because each small marker is on the scale equal to 5 volts), 33 V (because each small marker is on the scale then be equal to 1 volt)or  6.6 volts (because each small marker is on the scale equal to 5 volts), 33 V (because each small marker is on the scale then be equal to .2 volt)

And just to be pedantic, If it is reading 2 of the small markings beyond the second marker, then you would be seeing  110V (because each small marker is on the scale equal to 5 volts), 22 V (because each small marker is on the scale then be equal to 1 volt)or  4.4 volts (because each small marker is on the scale equal to 5 volts), 33 V (because each small marker is on the scale then be equal to .2 volt) - I must admit that copy and paste make s it very easy to be pedantic!!!

If you are not sure what voltage is present, you should test the connection by setting your scale to the highest AC voltage before applying the probes.  If you apply the probes to a DC output, the voltage is rectified anyway. If your setting is too low say 12 or 14 volts and you have it on the 10 volt selection, the dial will race to the right but generally speaking, no harm will be done. just disconnect the probes or turn it off and reset to the higher voltage selection.

What you cannot tell very easily is what current the transformer is putting out. Very few transformers will put out enough for the sudden current flow that a point motor generates and you would do wise to have a Capacitor Discharge Unit to power your points. 

Are you referring to a Triang OO Jinty and if so what vintage or what type do you have? The older locos were notoriously heavy on power and you transformer may not be keeping up?
Perhaps a little more information from you and perhaps a bit of feedback as to how simple or complex this was for you, but hope this helps 

Regards from Melbourne

Trevor

Thank you Shaun and you are welcome Peter.

Because I am a bit slippery when it comes to typing, a typo or two appeared on the original. I must hit a wrong key when copying and pasting so perhaps it is not so easy to be pedantic but I digress… the original has been edited

Peter, your transformer may well have been labelled say 18VA or 24VA or similar. a VA is a Volt times an Ampere so if your output is 12 volts, then 18VA would mean that you have 1.5 amps ready to power your train which should be more than adequate but of course I cannot see what you are actually powering with it. 16V AC would be producing 1.1 Amps at 18VA or 1.5 at 24VA and so it goes. The other variation of this is the Watt which is also a Volt multiplied by an Ampere. Using VA sounds more scientific and blinds the general public! 

Many years ago, we had a washing machine that when it started a cycle, the lights in the house would noticeably dim momentarily. If you have not got a capacitor discharge unit the effect on your trains and transformer would be the same in a smaller scake with current flow being drained by the point motor. 
I noticed you said you put two 16V AC connections on your transformer?  Nothing wrong with that in principle but what are they actually powering?  I suspect that there is something heavily draining on your system or a slight fault. 
 I have  protection resistors on my home made transistor throttles. Because I sometimes but seldom double head, I do not have a problem. Another modeller came  over and tried to run a quadruple loco (a bit embarrassing on a 4x8 but there you go…) but after 3 locos, the power supply just dropped off due to the protection I put in.  I wonder if you have done something similar?


Anyway, let me know!


Regards

Trevor

Sorry, Peter.  I wasn't being difficult.

I was trying to keep it simple.