Editing Railroad switch (section)

=== Stub switch ===
[[File:Railroad switch Boucher.jpg|thumb|upright|Closeup of a stub switch in Pennsylvania]]
[[File:Stub switch at Welsh Slate Museum.jpg|thumb|upright=1.1|left|A narrow-gauge ''stub switch''—this switch has an additional piece of movable rail instead of a frog.]]

A ''stub switch'' lacks the tapered points (point blades) of a typical switch. Instead, both the movable rails and the ends of the rails of the diverging routes have their ends cut off square. The switch mechanism aligns the movable rails with the rails of one of the diverging routes. In 19th century US railroad use, the stub switch was typically used in conjunction with a [[harp switch stand]].

The rails leading up to a stub switch are not secured to the sleepers for several feet, and rail alignment across the gap is not positively enforced. Stub switches also require some [[flexibility]] in the rails (meaning lighter rails), or an extra joint at which they hinge. Therefore, these switches cannot be traversed at high speed or by heavy traffic and so are not suitable for main line use. A further disadvantage is that a stub switch being approached from the diverging route that is not connected by the points would result in a derailment. Yet another disadvantage is that in very hot weather, expansion of the steel in the rails can cause the movable rails to stick to the stock rails, making switching impossible until the rails have cooled and contracted.

One advantage to stub switches is that they work better in the snow. The sideways action of the point rails pushes snow to the side, instead of packing the snow between the points and the rail in a more modern design.

Stub switches were more common in the very early days of railways and their tramway predecessors. Now, because of their disadvantages, stub switches are used primarily on [[Narrow-gauge railway|narrow-gauge]] and branch lines.

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