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Track sensors for Trains

Postby gbtrains » Sat Apr 07, 2018 8:20 pm

Hi all
I am wanting to use an alternitive to T Gauge senors when to stop trains and go again .
Could anyone let me know how to do the under track sensors and what they are as I will need this to be done on one my layouts.


Regards
Graham :D
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Re: Track sensors for Trains

Postby dkightley » Sat Apr 07, 2018 9:01 pm

There are a few ways of identifying the location of a train at a location on the track. The ones I know of fall into two basic types.....where the train either obscures a sensor detecting light waves of varying frequencies (eg white light, infrared, etc) or interrupts a beam of light, and where the train is sensed by use of some form of radio frequency or magnetic sensor.

The TGauge sensors are of the former type....a beam of light is interrupted by the train.

What is more important than the sensor.....is what the sensor is attached to, either some form of control circuit that is linked to a speed controller, where on detection, the train is slowed down or stopped, etc. Another control device could be simply a relay that reverses the polarity of the power to the track, effectively reversing the train...but in a totally non-scale way!

I have used LDR (light dependant resistor) sensors on The Bridge for over a year....and they are connected to a microprocessor controlled train control system that controls three separate trains. You'll have seen the system running at Sheffield. And I'm in the middle of upgrading the system by replacing the whole system with a DCC based software controlled system based on various kits from MERG.
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Re: Track sensors for Trains

Postby gbtrains » Sat Apr 07, 2018 9:28 pm

HI Doug
Thanks for the info

Getting stuff ready for Ribbleshead Layout for what I am needing in electrical things.

Just ordered the base boards ( laser cut and will be of 20 foot long.

Will get on and the LDR's then.


Thank you for your advise.

Graham :D
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Re: Track sensors for Trains

Postby gbtrains » Sat Apr 07, 2018 10:02 pm

Hi Doug

I forgot to ask what size and and what power do they use?

Graham :D
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Re: Track sensors for Trains

Postby dkightley » Sat Apr 07, 2018 11:31 pm

Graham

You'll need to have some basic knowledge of electronics to use LDRs (light dependant resisters). If you don't, then you'll need someone who has to design a circuit to do something that can connect to whatever you're intending to control your layout.
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Re: Track sensors for Trains

Postby martink » Mon Apr 09, 2018 1:07 pm

There are at least two other commonly used detection techniques, but both have potential drawbacks for T gauge:
- track circuit / current detection - this sits on the power feed to each section, and detects if a loco is present. The low currents needed by T gauge locos and their poor pickups potentially make this unreliable.
- magnets and reed switches - a bit tricky given that T uses steel rails!

In another post, I've just pointed Nutter at Heathcote Electronics who offer detection and automation products for larger scales, but alas I don't know how well they would work for T. It might be worth talking to them, then buying one of their detectors and seeing how it behaves. Or one of you giving it a go first, since you seem to want to do similar things.

https://www.heathcote-electronics.co.uk/index.htm
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