Show vehicle speed
From OpenTTD
A patch that displays the current vehicle speed in the vehicle information window.
[edit] Description
Once this patch is activated, you'll know at any time how fast your vehicle is moving. The speed will be either displayed in km/h or mph, depending on your settings. You can change the distance units in the Game options window.
[edit] Use
This feature is enabled by default. You can disable it through the configure patches -> interface window or use the following syntax in openttd.cfg:
[patches] vehicle_speed = false

