Electric stop, start and reverse for 4.5V battery trains

[John Hill]

Start, stop and reverse for 4.5 volt battery trains..

Sure, Lego supplied track side stopping and reversing devices for the 4.5 volt battery trains but this is something different, this is a method of controlling your battery trains remotely by electric means.

The train runs on batteries in the normal way but when it reaches the conducting track one of three things will happened depending on if the rail is energised and if it is which polarity it is energised.

If the conductor is not energised the train will continue on, if energised the train will stop and when it is deenergised the train will start again and the direction it goes depends on the polarity.

Rechargeable batteries take a charge while the train is stopped.

I have a train running back and forth on a section of track where there is not enough room for a layout. I have used a simple electric timer to control power to the conductor sections of which there is one at each end of the track. The train stands until the timer drops the supply to the conductor and the train starts off down the track until it reaches the other end where it stops for a little while then the trains starts off back up the track and the cycle repeats.

The circuit is simple enough, the two under train contacts are connected to a rectifier circuit which charges the battery. Two relays are activated by current from the under train contacts, relay number one is a simple relay with normally closed contacts and when activated stops the train. Relay number two is a special type of relay which will move when one polarity is applied to the coil and will not move back until the opposite polarity is applied. Relay number two sets the direction of train travel and the type is known as a bipolar latching relay. I am using 5V relays.

Some pictures of the required bits and pieces..

The little circuit board..

The contacts fit neatly under a train wagon..

Little plastic ramps I made for the each end of the conductor rail, without these the contacts are likely to bounce and derail the car..

Edited January 19, 2016 by John Hill

[Hod Carrier]

What a clever idea. Neat, simple and elegant.

[Dutchiedoughnut]

I am thinking of something similar for PF trains, since my intended layout doesnt loop around

[John Hill]

Ooops! I had a few errors in the circuit and have made corrections to it.

Edited January 19, 2016 by John Hill

[dr_spock]

Great idea. I think a video of it in operation would be cool. Does the train ever have enough momentum to fly past the control rail?

I am thinking of something similar for PF trains, since my intended layout doesnt loop around

I did something for end of line to stop, pause, and reverse PF trains using a PF infrared control commands and magnetic train detection:

[John Hill]

The train stops about one third down the rail. I am working on the second one of these so that I will have two battery trains to play with and will think about a video when I get it all running.

[LEGO_duden]

Very cool idea, what kind of battery are you using?

[John Hill]

Here is a video...

Lego Train Reversing by MrJohnHill, on Flickr

.....I hope it works as I have sweated blood to get this uploaded etc.

The first train has 4 NiCd size AA the train in the video has 4 AAA alkaline cells.

Edited January 21, 2016 by John Hill

[bricks n bolts]

Very nice idea It's cool you have a method to control the train and recharge the batteries at the same time.

For the ramps did you try using cheese slices? Something like :