|On the other hand, the Faller roundhouse, pictured here in N gauge, has multiple stalls.|
There needs to be easy access to the stalls from the track, and so most layouts are based on a track plan that includes a turntable.
A Roundhouse with a Turntable
A track plan that uses both a roundhouse and a turntable benefits from:
- easy expandability (adding more stalls);
- easy access to stalls;
- somewhere to turn the locomotive around.
A Roundhouse with a Sector Plate or Traverser
A sector plate is a (usually) manually operated track selection device. It can be thought of as a piece of track on a moving platform which can slide along a horizontal plane (usually called a traverser), or at an angle (kind of like a hinged piece of track.)
Sector plates allow for selection of rolling stock (i.e. locomotives stored in a roundhouse) but do not give the ability to turn them around.
Creating a sector plate can be technically challenging, but ultimately it can help solve issues relating to space for both roundhouse layouts and those with multiple sidings.
For those who don't have the skills, then there is also another way - to use a three way point.
A Roundhouse with 3-Way Points (Switches, or Turnouts)
Three way points are expensive. They occupy much the same space as a Y-turnout in most track geometries, and so are quite compact. Whether or not they're prototypical is probably also a point for discussion.
Nonetheless, many manufacturers who supply three stall roundhouses have made them compatible with their 3 way points (switches, turnouts) and so they do offer a quick and easy way to provide access to multiple locos.
However, as with sector plates, they don't allow for turning around the loco, which is where the turntable has a real advantage.
Other Track Plan Ideas for Layouts with a Roundhouse
Finally, it is possible to use multiple points (switches, turnouts) to feed track to the roundhouse, but usually they will need to have a bit of give in the track.
Lining up the roundhouse stalls with the track becomes an issue when using multiple points, curves, and other pieces of track.
However, some layout designs simply use the roundhouse as a feature purely to store locomotives, and have lines running out from them in all directions - in such cases there's no need to try and merge the track into a single line.