From #openttdcoop wiki
The next-generation TGV-concept (TGV_ng)
- First of all look at the image to the right.
- The TGVs have a new design! Engine - 3 Passenger - 2 Mail - 3 Passenger - Engine. Add this a second time and you've got one TGV, 10 tiles long.
- We do not longer build any Hubs larger than T-Hubs! No Cloverleafs, never! Since the TGV-Concept is all about speed, we do not accept these large Hubs in the next generation of TGV-networks.
- We no longer build long straight tracks from edge to edge. In exchange, we build intelligent tracks wherever needed and whereever they fit into the landscape (as shown in the picture).
- Since our T-Hubs are not slowing down the trainspeed a train can go over a large number of hubs as well as on straight tracks. This, in the end, will shorten our pathes from station to station (remember: we can't build diagonal lines for reason. But with TGV_ng we have some kind of zigzag-routing for our trains).
- The TGV_ng network is expandable: if a certain part of a network is under heavy load, it can easily be expanded by adding a T-Hub and routing trains over another part of the network.
- Additional ideas: It is still difficult to add another (second) track to the existing track. One idea is to make an outer box (mainline) with a 2x2 track. For larger games (like 1024*1024) we could make an outer box with 2x2 and an inner box with 2x2, connected by a number of 1x1 lines - and still only T-Hubbed!