The 3 common options for control of 2 trains on the same track:
- DCC is the easiest to operate and wire, but requires your locomotives to be fitted with decoders. The system components are more expensive than traditional power packs, as well. Costs for a starter DCC system, plus a second throttle will run $220-$300 depending on exact components and discouts. This cost does not include decoders, which come pre-installed in some locomotives.
- DC block wiring. You divide your track into electrically isolated blocks. Each block is wired to an electrical switch (commonly a toggle switch on a control panel) which controls which power pack is linked to which block. Each train is independently controlled by a separate power pack. The power pack is connected to the same train where ever it goes on the layout by aligning the block toggle switches correctly. Your sketch would probably call for 6-7 blocks to give the 2 trains room to move without getting into the same block at the same time. Once 2 trains are in the same block, they are under the control of the same power pack, and cannot be controlled independently.
- Section wiring/control. Commonly used on toy train layouts where there is very little sharing of track between trains (not your situation). Each section of the layout is independently wired, and has its own power pack. The drawback to section control, aside from the expense of extra power packs, is that when a train is crossing from one section to another, there is a moment of electrical confusion with both power packs supplying power. Since you can't match the power packs perfectly, there will be surges or slowing at the section boundary. In addition, when the wheels span the section insulator, there will be a fault current flowing through the wheels and wiring that is proportional to the voltage difference between the 2 power packs. This fault current is often not protected against by circuit breakers, and may cause damage to delicate electronics. It also tends to pit the wheels.
DCC or block control would be the normal 2 choices for your situation. There are many threads on the forum about selecting DCC or wiring for block control.
yours in wiring