Automatically starting and stopping a train

[Steadfast]

Hi all,

Help needed please!

So, I'd like to be able to get a train to leave the fiddle yard, do one lap and then wait in the fiddle yard before automatically departing again a couple of minutes later, so I can concentrate on shunting the top level of the layout. As the stop start is in the fiddle yard, I'm not worried about anything fancy, slowing to a realistic stop etc. 

Effectively what I want is an automated on off switch in line with the 12 v DC track feed.

The line concerned is a plain track oval, no other lines are concerned.

Do I need to go to the hassle of fitting a unit such as this https://www.brimal.co.uk/model-rail-station-stop-timer-5-seconds-to-120-seconds.html or is there a single component I can purchase for a few pounds and connect in line to the track feed? The simpler the better, as it means less modification to the fiddle yard trackwork.

I believe a relay may do the job but my knowledge in such areas is severely limited, hence the thread!

Thanks

 

Jo

[Ian Morgan]

I think the module from Brimal is about as simple as it gets to do what you want. If you are unsure about electrics and electronics, then buying a pre-built module that comes with instructions and email or telephone support is advisable.

 

 

[WIMorrison]

The cost of this is only £12.50 including VAT and it does what you want - how much cheaper do you want it to be?

[Theakerr]

Do you care if the stop and start are 'abrupt'?  If not then a simple relay with a time delay built into it and activated by a reed switch will work.  If interested I can direct you to said relays from china.

[Steadfast]

Thanks for the replies guys.

It's not the cost I'm worried about directly (Indeed I think the brimal system is good value) it's more that I'm trying to make the least amount modification to the track, wiring, and baseboard, hence asking about a simple inline switch that operates automatically is such a thing exists.

I'm not fussed about whether the stop and start is abrupt, it'll only be a DMU out of view to the public

 

Jo

[DCB]

I think some form of slowing will be needed if you use rtr stock with tension lock couplers as they tend to over ride when doing emergency stops.  Peco / cornhook / H/D and Kadee couplers shouldn't need anything fancy

[Theakerr]

I have used sudden stops for years in my hidden sidings with no problems if the tension locks are all at the same height.  In any case if it is a late DMU model it is almost certain to have the loop type coupler.  The reed switch to a timed relay will involve minimal track modification  and the relay can be mounted anywhere.  All that is needed is a 12V or 5V (if using an Arduino compatible relay) source.

[Ray H]

I've had some success using Light Dependent Resistors (LDRs) on our club layout. I have a reasonably simple circuit that operates a reversing camera/monitor combination to show when a train is berthed at a platform - the camera being live when there's something covering the LDR.

 

The LDR could be set up to trigger a timer circuit that energises a relay which, when energised, isolates the section of track that the train has come to a stand on. The train passes over the LDR and the timer circuit starts, energising the relay. At the end of the time period the relay de-energises and track power to the section is re-applied.

 

The chance of the gap between vehicles re-starting the timer circuit can be solved by extending the timer period and placing the LDR some distance before the track section which is controlled by the relay.

 

It isn't fail safe - track power disconnected when relay energised - but it does mean that by turning the circuit off if required, the train can simply keep running.

 

Perhaps its something a little more complicated than the OP needs but the concept might be useful to others.

[Ian Morgan]

Looking at the Brimal module, it appears to be just a reed switch (operated by a magnet fixed to the bottom of the train, with a 555 timer setting the delay, and a DPDT relay. They suggest a separate, switched block section in the station, but you could simply wire the relay into the main feed and shut off the entire loop if you want.

 

 

[Steadfast]

Thanks for the further replies.

I've done some looking around, and I reckon the brimal device that uses a reed switch (rather than the light detector one) is probably my best way to go. Looks to basically be the components I need to do it DIY, but on a circuit board and with an instruction manual for installation too! Seems to be the least amount of drilling and cutting compared to other options.

Also, I have loads of tiny high strength magnets so that should be fine for doing the reed switch. 

I should also add, this is in N, and the couplers seem pretty solid with sudden stops and starts

Jo

 

[Robert Stokes]

I also have storage loops in which trains (up to 6 coaches or 18 wagons) stop automatically and abruptly in isolated sections. I have carried out extensive trials of this arrangement, before building a station above them, and there has been no trouble. I think that a key factor preventing trouble is that the trains are travelling in a straight line before they stop.

 

Robert