Accessory solenoids - burnout possible?

Yes, for the crossing gates (and semaphores.) They are generally designed to dissipate heat only for intermittent operation.    I don't know when it comes to the vibrators.

Yup. Fried a couple Gateman houses last year on the Christmas layout.

I've seen the Banjo Signal cooked, so that can happen.  I know the vibrator on the barrel car gets pretty hot after a couple of minutes running, so I imagine some of them are designed for intermittent operation.  OTOH, stuff like the searchlight with the vibrator run for hours with no problem.

Thanks for the replies.  Last year I converted my switches to fire with capacitor discharge (with this forum's help), and it recently dawned on me that accessories are also at risk.  Dale, I'll study up on the interval - timer circuits.

Thanks,
Chris

Another option is a resettable thermal fuse (PTC) or a thermal switch.  Here's a PTC protecting the coil on an activation track.  If you can co-locate a thermal switch on the mechanism - impractical on an exposed banjo but possibly on a gate solenoid(?).  Both devices are about $1 but would require some study to select the correct parameters.

 

Depending on what kind of timer you choose, one issue is memory.  That is, if you have a timer that limits the ON time, what happens if the user immediately re-triggers the mechanism over and over....such as a kid at a train show fascinated by some mechanism.  So if you go with a timer circuit consider one that also has a OFF time setting that keeps the mechanism disabled for some interval between activations.

 

I use the circuit shown below for keeping heat low in the solenoid of a Lionel #45 Gateman for some extended period of time. 

<small>But I don't trust it for trains parked long-term in the controlling track section; when a train is parked there, I use another ciruit to cut off power to the Gateman (—he goes back into his shack and comes out again when the train is again powered on).</small>

 

For this circuit, a 12 VAC accessory transformer provides power between points "D" and "E".

A Relay <small>(5 VDC coil)</small> is used to turn the Gateman On/Off.
The Relay coil itself is energized when metallic train wheels and axles span the outside rails of a control section in which one of the rails is insulated from the other.

Diodes D2 and D4 rectify the AC into half-wave DC.
Diodes D1 and D3 shunt out the reverse voltage when the solenoid or relay coils are turned off.

Capacitor C4 smoothes out the DC for the relay.

Capacitors C1 and C2 store up a charge for "kick-starting" the Gateman's solenoid into action.
Capacitor C3 does the same thing for "kick-starting" the Relay.

Resistors R1, R2, and R3 serve to limit current-flow (and hence the heat).