The system architecture is built around the Märklin CS3 (60226). Two boosters are connected to the CS3 via the CAN bus. Including the CS3's internal booster, the system can supply a total of approximately 9 A of digital current. This is more than enough to power 20 simultaneously active trains, even considering that not all will be moving at the same time.
During the design phase, the layout was preliminarily divided into three zones as follows:
Level 0 (hidden stations 1 and 2) and the southern ramp of the main line are powered by the CS3's internal booster. Level 2 (hidden station 3) and the main line's northern ramp are powered by a 60175 booster. The secondary station, the entire secondary line, and the Viessmann Car Motion IR transmitters are powered by a second 60175 booster.
Three mobile stations are also connected to the CAN bus via a 60145 terminal: two are first-generation (60652) and one is the latest (60657). These are dedicated to manual maneuvers in the secondary and main station yards. Therefore, even considering the two CS3 controllers, there are five controllers available for manual control of the rolling stock.
The block feedback system is based on the S88 Link module (60883), to which five S88 AC modules (60881) are connected on bus 1 and an older S88 (6088) connected on bus 3, for a total of 112 available feedback channels.
The layout features a total of 67 points for the railway section and 8 for the Car Motion. Of the 67 points on the train, 5 are slender, including one curved R3, while 62 are standard, including 7 double English switches, 3 triple switches, and 9 curved R1 switches.
For the signaling, I used signals from both Lineamodel and Essemme, for a total of 16 devices.
The buildings are illuminated by self-built LED lights, obtained from LED strips that were appropriately sectioned and then installed to ensure mechanical stability and proper heat dissipation. The street lamps, station lights, station signs, and switch lanterns are all powered by 12V DC.
All these accessories are controlled by one Märklin M84 decoder (60842) and three M83 decoders (60832), as well as six ESU Switchpilot Plus decoders (51831). Almost all the turnouts are equipped with Märklin decoders (three 74466 and four 74461/2) located under the track bed.
I initially used a 32 VA Märklin AC transformer (60052) as the power source for all the layout accessories. This was intended to power all the LED lights, the traffic lights, as well as the eight Car Motion turnouts and the level crossing. I later realized that this solution had three problems: the LED lights flickered when filmed on video, some signals were too bright due to the voltage at the upper limit (16 V) of their application range, and finally, I was loading the Märklin AC transformer asymmetrically. In fact, the ESU switchpilot decoders do not allow the use of the negative part of the half-wave, so all the LEDs had to be connected to use only the same positive half-wave. This asymmetrical load could have created problems for the transformer. I therefore used a 12 V DC 100 W switching power supply for all the LED loads, while I reserved the transformer for only a few solenoid-type loads.
In addition, the LED strips that illuminate the three hidden stations are powered separately with another dedicated 12 V DC 100 W switching power supply.
Therefore, the layout is powered by six switching power supplies and one transformer: three for the CS3 and the two boosters (60041), one for the S88 Link (66360), one for the LED strips, one for all the LED lights, and finally an AC transformer (60052) for the rest.
IMPORTANT! All three 60041 power supplies should be plugged into a power strip with a switch and turned on simultaneously. I've had two instances where plugging in the 60175 Booster power supply asynchronously with the CS3 caused the booster to fail (under warranty). Since then, I've used the power strip, and the problem hasn't recurred. I believe it was a design issue; in fact, after the second failure and my return, the device was unavailable from the manufacturer for some time while they were working on a fix.
The image shows the architectural scheme of the system developed to control the layout. The CS3 is then connected to the PC via Ethernet. The PC runs the iTrain software, which effectively replaces the CS3's control logic. It's the computer program that sends commands to the CS3, which in turn forwards them to the layout, and receives feedback signals from the CS3, which in turn reads them from the S88 Link buses. We'll see in the dedicated section how the system is programmed in iTrain, the true heart of the entire system.
It's always possible to manually control rolling stock while the PC controls the rest of the traffic; simply tell the software that the train is operating in manual mode. The software continues to monitor its position, but leaves the movement to the Mobile Station or Central Station.