Tam Valley Depot QuadLN Loconet servo controlers and IO

I have been doing a lot of research for a cost effective switch controller and actuator that would give me the biggest bang for my buck.

What I wanted was the impossible. I wanted to be able to control a switch from either a control panel, the throttle or finally JMRI. I also needed to know what position the switch was in at any time, especially when booting up the layout for a session. Bottom line, it all came down to cost, not just for the controller, but also the drive that would actually move the switch.

The Tam Valley Depot QualLN and a SG90 9g servo fitted the bill perfectly.

Firstly the servo. I buy these form Hong Kong on Ebay. I buy a 12 pack and having purchased a pack last week, they come in at R33.82 per servo. End of story there.

Secondly and lastly, the QuadLN. What does this beast "not do" would be easier to answer. However, here is the list of what it can do and what I wanted it for.

• It can control 4 separate switch "areas". So if you have a crossover with two switches, one servo output would control both servos for the two switches.
• There are then 8 separate inputs and outputs for whatever you want. 4 of them are standard for the fascia controllers and LED's, but if you do not need fascia controllers and indicators, they are available for other IO's. I will be using these for the fascia controllers.
• There is then the additional 4 I/O's for something else. In my case I will be using these for Block detection. I can theoretically then detect a mainline, a passing siding to that mainline, and the blocks on either side of the mainline.
• The QuadLN is a Loconet device that can hook into the Digitrax Loconet and all messages are sent over the Loconet and not by hooking the device to the rail power.
• I do not need sensors on the servos to show alignment as this is remembered in the QuadLN when a switch is either thrown or closed. So no matter what, even if the power is lost, the QuadLN will remember the switch position when power is restored to the layout.
• Routes can be programmed directly into the QuadLN. so one press of a button on a ladder would change all the switches down the ladder if so set.
• And lastly and very importantly for me, selected switches can be locked out if required. So if I wanted to lock out certain mainline switches during an operating session, I could do so. This could put all mainline switches in the control of the dispatcher. The respective fascia controller push buttons would thus not be operational. However, when an operator requested track and time at one of the switch locations or area, the dispatcher could temporarily hand control back to the operator by turning on the push button functionality for the respective switches. Absolutely awesome.
• Lastly, with the feedback of switch positions from the QuadLN, this could be tied into a nice signalling system one day.

Below is one of the QuadLN's fitted under my yard at Whitefish. If you look carefully, you will see 2 sets of 2 servos linked together. This is to control 2 separate crossovers on this side of the yard. There are a further 2 servos controlling separate switches.