A machining spindle that includes a tool-holder shaft (2), a first actuator connected to a coupling member (11) slidably connected to a first section (21) of the shaft to rotate the shaft, a second actuator connected to a nut helically connected to a second section (22) of the shaft to move the shaft axially and a control rod (24) of a tool-holder attachment system connected to the second section by a full connection. The spindle includes a locking arrangement (40) mounted movable between the first and second sections by a switchover arrangement (50), between a first position in which the first and second sections are in full connection and a second position allowing axial movement of the second section relative to the first section, enabling the control rod to be moved axially under the action of the second actuator to control the attachment system in a released position of the tool holder.

A rail drill drive train can include a common drive end between a single drive motor and a common gear. A speed train end can extend from the common gear to rotate the drill spindle. A feed train end can independently extend from the common gear to advance and retract the drill spindle. The speed train end can include a sprag gear so that, without unmeshing any gears, the drill spindle is not unnecessarily rotated in the reverse direction when the drive motor is reversed to retract the drill spindle. A rail drill control circuit and related sensors can enable automatic operation throughout the complete drilling cycle without any manual input from the user other than starting the cycle. Such a fully automatic drilling cycle can minimize overall cycle time to preserve battery life and can free the user to perform other tasks between drill moving and clamping operations.