The following glossary is arranged alphabetically with each term catalogued by first letter. Select a letter below to begin.
Johnson bar
The manual reversing lever of older steam locomotives.
Joint
An end to end mechanical rail connection using a rail joiner to maintain precise alignment.
Joint bar
A formed-steel bar, bolted in place, used to join sections of prototype rail.
Journal
The load bearing part of an axle. The weight of the axle is carried by the journal bearing, which is enclosed by the journal box.
Junction
A location where main and/or branch lines diverge or cross each other.
