On acoustic and electric pianos, the front rail is a horizontal wooden rail that sits underneath the front point of the keys. It houses the front rail pins, metal pins that the keys are inserted into. The front rail and pins acts as a catcher for the key when it is pressed, reducing its side to side movement and as a starting point for the correct amount of key dip. The front rail is attached and raised above the key bed.
The size of the rail depends on the type of piano – Rhodes and Wurlitzer electric pianos for example, have a thinner and lighter balance rail than in grand pianos, but the purpose is the same – to catch the key when pressed. The front rail must be as level as possible to allow for even key dip for all keys. Key dip is then finely adjusted by adding paper punchings on the balance rail pin between the rail and the key. A green front rail felt is inserted on the pin as well to eliminate clicking between the key and the front rail.
A similar type of rail is found at the centre of the key. This is called the balance rail and is designed to catch the key when it is pressed via the balance rail pin.
Hohner Clavinets do not have a front rail as they are designed more like electric keyboard instruments. As the hammer tip is directly attached below the key, and therefore strikes the string, the need for this type of rail is unnecessary.
