Bump and Go O- gauge handcar?b Maybe using DC power?

Not clear on what you're asking.  If you want bump-n-go, then why not just buy a handcar that already has that feature?

OTOH if you are eyeing a particular handcar that does NOT have bump-n-go capability, how does it reverse direction?

I've never looked, but I'd be surprised if there's an O-gauge handcar with enough internal space to install a traditional electronic reversing circuit board.  If my ignorance is true, I suggest you're better off performing the reversing electronics/logic externally...rather than trying to (1) install a reversing circuit board inside the very tight quarters of a handcar, or (2) mechanically modify the handcar to install a mechanical bump-activated slide-switch that reverses polarity/direction to the DC motor.

I'm imagining a handcar with an internal DC motor with negligible internal electronics.  The DC polarity/voltage of the track determines direction/speed.  External electronics detects (e.g,, using insulated-rail triggering) when the handcar reaches the end of the line and then reverse the polarity of the DC track voltage to change direction.  The polarity reversal could be performed by inexpensive ($5-10) relay modules...some of these have timer capability so you could even have the handcar stop at each end, wait 5 seconds (or whatever), and then go back the other way.  I'd think you could even do all this without firing up a soldering iron if that's an issue...

Or, Dallee and others have off-the-shelf back-and-forth "systems" that might be exactly what you need.

Thanks for your input Stan,

The deal here is that the only bump and go handcar I can find on the internet was made by MTH, and the workmen are ridiculously big.  I don't think they even make it anymore.   The most recent one was had Trump figure and Uncle Sam figures., and

The closest thing to scale is the IDM industrial rail trolley, sold by IDM and once offered by Atlas.  It looks pretty close.

I was just hoping that there was some device to place on the two ends of the track section which, when bumped, would just switch the polarity or power inputs in the inner and outer rails.  I mean really, how hard could those be to design?

I'll check out the Dalle website to see if they've got something.

Thanks,

Mannyrock

Obviously not hard at all.  Here's a Dual-Coil Latching Relay, for $8.77.  Wire your DC track voltage through the DPDT contacts to reverse the polarity on the rails.  On each end, you wire a pushbutton that activates one of the coils and switches the relay.  At the other end, another pushbutton activates the other coil.  Job done.

Stan,

I checked out the Dalle website.

It looks like the DC 5amp senses, back and forth unit would do it, though it will only handle 5 amps.

I wonder if an O Gauge motorized unit would run on a DC system with only 5 amps capacity?  (I don't even know if the 5 amp refence is to an AC power supply, or the DC output power to the track.)

Pretty confusing to an electronic idiot such as myself.  :-)

Mannyrock

Did you read my solution?

@Mannyrock posted:

...

The closest thing to scale is the IDM industrial rail trolley, sold by IDM and once offered by Atlas.  It looks pretty close.

...

Presumably you mean the Industrial Rail handcar?  The Industrial Rail trolleys have bump-n-go.

Assuming you meant handcar, it appears that some versions only operate in the forward direction.  I didn't bother searching OGR but I'd think someone has already looked into this.  I'd think there are some diodes or a bridge rectifier INSIDE the handcar to convert standard O-gauge AC track voltage into DC for what I'm guess is an internal DC-motor-gearbox.

So if my guess on what's inside is correct, the first task is to convert the IR handcar for bi-directional operation.  The simplest would be to bypass the internal diodes to directly drive the DC-motor from DC track voltage.  Thus, the handcar would operate in both direction based on the polarity of the DC track voltage.  This might require soldering though what I'd call a basic level.

Without such a modification any DIY scheme or even any off-the-shelf system such as the Dallee would not work.

Separately, a 5A trolley system, whether that be AC or DC will be way more power than any handcar would need.  I'd think 2 Amps max and more likely only 1 Amp.

@Mannyrock posted:

I was just hoping that there was some device to place on the two ends of the track section which, when bumped, would just switch the polarity or power inputs in the inner and outer rails.  I mean really, how hard could those be to design?

I told you how to do it for simply and for peanuts, and you didn't even bother to respond.

Azatrax makes a controller that seems to do what you want.  Stan is correct the bump and go have DC motors.   Just remove the bridge rectifier and wire the motor directly to your DC powered rails.  Azatrax will reverse and also change acceleration.

Specifically, Azatrax will decelerate your vehicle, stop it, reverse it, restart it, accelerate it  and repeat the same at the other end.  Look Ma, no hands.

https://www.azatrax.com/back-and-forth.html

John is a ghost today !

GunnerRunner, thanks for your excellent simple-to-do solution.  I just saw it a minute ago.    I didn't see your reply yesterday because while you were posting it, I was looking at the DalleWebsite and then typing up my questions about the Dalle system and pressing POST.  After posting it, I signed off until this morning.   

Thanks to Stan and everybody else for the thoroughly informative answers.

I am going to use a small dedicated DC transformer, from an HO train,  mounted under the table to power the handcar track, because it will run on a dedicated short track run.  The transformer will cost about $5 used at the flea market.    And, although I may fail, I think I'm going to try John's cheapest suggestion first.   (Finding big and sensitive  push buttons for the car to run into may be a challenge, especially since they will have to be mounted upright.  May those standard ,cheap Lionel "big red buttons" in black plastic squares would work.   

Thanks to the advice from all of you guys a year ago, I bought last year a pretty nice bridge rectifier, so if the HO transformer doesn't put out enough DC juice to power the car, I can try to power it with the old 1099 transformer that I already have mounted under the table (which I use to power my free standing steam whistle unit.)

Mannyrock

GunRunner,

Two quick clarifications on the Dual-Coil Relay please,

1.  On the website, under Product Description/Category:  I must select either (i) Relay, or (ii) Power Relay over 2 Amps.  Which one should I select please?

2.  As to the pushbuttons on the ends, I assume that these would be momentary ON buttons?  Is that right?

Thanks,

Mannyrock

@Mannyrock posted:

GunRunner,

Two quick clarifications on the Dual-Coil Relay please,

1.  On the website, under Product Description/Category:  I must select either (i) Relay, or (ii) Power Relay over 2 Amps.  Which one should I select please?

2.  As to the pushbuttons on the ends, I assume that these would be momentary ON buttons?  Is that right?

Thanks,

Mannyrock

Click on the link I posted, it takes you directly to the relay.

Dual-Coil Latching Relay

As for the pushbuttons, I'd consider some spring leaf contact strips that would offer the ease of depression needed for the task.  These are commonly found in things like pinball machines.  If the speed coming into the end of the track is too great, you can just insulate the center rail for a distance and stick a resistor in to drop the voltage (and thus the speed) to the desired terminal speed at the contact point.  The switches, whatever form they take, are normally open momentary on contact style.

Thanks John,

When I first clicked on the link, the product spec button was selected for the power relay over 2 amps.  I wasn't sure whether you had clicked that selection for me, or whether it was a random website default.   

Thanks very much. I'm ordering it.

Mannyrock

I can confirm that the MTH Bump N Go Trolleys run very well using a DC transformer.  They are also quite available.

https://www.legacystation.com/...-street-trolley-4694

https://ogrforum.ogaugerr.com/...mer-ok-for-bump-n-go

Just connect the - side to the outer rail and the + side to the center rail.

John

Considering DigiKey shipping will be ~$5 for the $9 RT424F12 dual-coil DPDT 12V latching relay, note you can get it mounted on a PCB with screw-terminals for not much more coin if you do Amazon...

As for end-of-track sensors,

As GRJ says, leaf switches are widely available in many styles and such.  For about 50 cents at DigiKey you can get momentary pushbuttons with a square keycap (sold separately) that might be more aesthetically pleasing as a bumper but to each his own.  Note that for the application at hand I think you want to select a switch with as little actuation force as you can find.  The EG1821 as shown requires 160 grams-force (about 6 ounces).  I can't say if this would be suitable for a bump-n-go but I just had them lying around.  Some pushbutton switches used in pinball machines have relatively high actuation forces to tolerate the frustrated pinball enthusiast!  Obviously you don't want to have to slam the handcar into the bumper at high speed just because you selected a pushbutton with unnecessarily high activation force!

Both the Dallee and Azatrax "systems" make reference to magnetic sensors to detect end-of-line or station-stop. This would be another option.  For example, you'd put a tiny ~25-cent Neodymium magnet (see photo) under the handcar and then a ~50-cent magnetic reed switch in the trackbed at each end.  When the handcar passes over the reed switch, it closes the switch just like bumping into a leaf or pushbutton switch.  The benefit with this method is the handcar does not have to bang into the bumper so no whiplash disability claims from your workmen.

As an aside the Azatrax controller I referenced is IR not magnetic.  However Azatrax is not the low cost solution but it automates.  I’ve implemented this already using a Super Streets vehicle.

Having been a pinball repair guy in high school, I can tell you that many of the contact blades have very low actuation force.

I love the idea of the reed switch and magnet, that's what I was coming here to suggest but Stan beat me to it.

I've posted this DIY scheme before but if you don't mind a little wiring (but NO soldering!), here's a way to "make" a latching DPDT relay using the insanely low-cost multi-channel relay modules widely available on eBay, Amazon, etc.

For example, for $5 each you can get a 4-relay (NON-LATCHING) module.

Yes, it requires attention to detail to make the connections as shown, but it might be the least out-of-pocket option.

Addendum:

Upon reflection, it may not be "obvious" how a latching DPDT relay would be wired up with end-of-track sensors in the first place.  Here's the same diagram above using the originally proposed latching relay.

I notice the off-the-shelf systems make a big point about station-stop functionality in the middle of a run.  Maybe this only makes sense for a trolley back-n-forth as opposed to a handcar.  But then again maybe there's a hill, curve, or other scenic point of interest on your run and you want the guys to get a short break!  Anyway, there's an argument to be made to "standardize" on a sensor type that would allow you to add functionality downstream.

Unbelievable amount of great info from you guys!  Thanks so much.

Stan, I hope you are printing out all of your colored pictures and diagrams, and putting them in a folder.  In a short while, you would have enough of them to print a great book!

Mannyrock

MTH 30-2508 Bump N Go Handcar

John

Truthfully, I think the reed switches and magnets on the cars to reverse the travel are the Cat's Meow for this task.  The lightweight bumper reverse cars have issues derailing some of the time, the polarity reverse with no impact seems like it would be much more reliable.