switch hum

[dado]

I have 1122 switches and 5122 switches. All work fine with the controllers and auto derails work fine. But when a train crosses each switch the solenoid is activated with a loud hum until they cross the switch. Is this normal? All have fiber pins at the short control rails.

[ADCX Rob]

All normal.

[lionelsoni]

Just don't park anything on a turnout with the track voltage turned up.  The same current that's making the hum will soon heat up a coil and melt the plastic that it is wound on.

There is a modification to avoid the problem; but it's not for the faint of heart.

[dado]

That is exactly it. I am in the process of wiring all my switches to fixed 14 volts along with the accessories.Many thanks!

[BigAl 956]

The hum is just one of many reasons why I do not recommend building a layout with O27 track and switches.

O22 switches for O track are designed to only energize the coil for a moment until they switch over.

O27 switches stay energized continuously when a train rests on a non derail segment causing the hum. They will also overheat and melt if you leave them energized that way for too long.

[ADCX Rob]

dado

That is exactly it. I am in the process of wiring all my switches to fixed 14 volts along with the accessories.Many thanks!

BigAl 956

The hum is just one of many reasons why I do not recommend building a layout with O27 track and switches.

O22 switches for O track are designed to only energize the coil for a moment until they switch over.

O27 switches stay energized continuously when a train rests on a non derail segment causing the hum. They will also overheat and melt if you leave them energized that way for too long.

You fellows both might then be interested in the capacitive discharge system that Bob has described many times right here in this forum going back over 10+ years now.

[lionelsoni]

You beat me to it, Rob.  I will add that powering these O27 turnouts continuously has much more risk to the turnouts than the original design.  It is an improvement only if coupled with something like capacitive discharge.  By far, the greatest labor is in the conversion you have already done--Adding the capacitive-discharge feature is easy by comparison.

[phillyreading]

Bob Nelson, have you looked at the posting "Train sounds bells and whistles?" I think you might know more about why an 027 switch can effect a new tender's whistle and bell feature when going over a switch.