Single-track road

A single-track road or one-lane road is a road that permits two-way travel but is not wide enough in most places to allow vehicles to pass one another (although sometimes two compact cars can pass). This kind of road is common in rural areas across the United Kingdom and elsewhere. To accommodate two-way traffic, many single-track roads, especially those officially designated as such, are provided with passing places (United Kingdom) or pullouts or turnouts (United States), or simply wide spots in the road, which may be scarcely longer than a typical automobile using the road. The distance between passing places varies considerably, depending on the terrain and the volume of traffic on the road. The railway analog for passing places are passing loops.

In Scotland

The term is widely used in Scotland, particularly the Highlands, to describe such roads. Passing places are generally marked with a diamond-shaped white sign with the words "passing place" on it. New signs tend to be square rather than diamond-shaped, as diamond signs are also used for instructions to tram drivers in cities. On some roads, especially in Argyll and Bute, passing places are marked with black-and-white-striped posts. Signs remind drivers of slower vehicles to pull over into a passing place (or opposite it, if it is on the opposite side of the road) to let following vehicles pass, and most drivers oblige. The same system is found very occasionally in rural England and Wales. Sometimes two small vehicles can pass one another at a place other than a designated passing place.

Single track

Single track may refer to:

Single track (mountain biking)

Single track or singletrack is a narrow mountain biking trail that is approximately the width of the bike. It contrasts with double track or fire road which is wide enough for four-wheeled off-road vehicles. In addition it is frequently smooth and flowing, but it may also exhibit technical rocky sections and may be criss-crossed with tree roots. Some trails are winding and flowing, while others are bumpy and challenging. Many trails offer features such as roots, logs and rocks. Single track paths can be ridden using a mountain bike, BMX bike or race bike. Single track riding can be quite challenging from a technical standpoint. Singletracks cover vast areas of both state and national park lands.

Trail building in the US

There are volunteers, both organized and rogue, that maintain and create single track trails throughout the country. The organized volunteers coordinate with park districts to modify the natural woods to accommodate single track bikers. Some paths are created from scratch, while others are modified hiking paths.

Single-track railway

A single-track railway is a railway where trains travelling in both directions share the same track. Single track is usually found on lesser-used rail lines, often branch lines, where the level of traffic is not high enough to justify the cost of constructing a second track.

Advantages and disadvantages

Single track is significantly cheaper to build, though it has operational disadvantages. If the single-track section is say 15 minutes long, the line would have capacity for only two trains per hour in each direction. Double track can allow up to 15 trains per hour in each direction if signal boxes are four minutes apart and provided all the trains travel at the same speed. This hindrance on the capacity of a single track may be partly overcome by making the track one-way on alternate days, if the single track is not used for public transit.

Long freight trains are a problem if there are not enough long passing stretches. Other disadvantages include the spread of delays, since if one train on a single track is delayed, any train waiting for it to pass also will be delayed. Also, single track does not have a "reserve" track that can allow a reduced capacity service to continue if one track is closed.