A somewhat lesser-known British designer named Edward Johnston devised the original lettering and logotype for London’s subway, known officially as The Underground and informally as The Tube.
The logotype is still in use today; the lettering was later adapted by Eric Gill, and most of us are familiar with the resulting fonts that bear his name.
This incarnation simulates the lettering tiles used by the system during the late twenties and early thirties.
For a lowercase space, use the underscore (_) key; for a bulleted space, use the equal (=) key.
See the chart below for lowercase numbers.
Windows users: make sure the “Num Lock” light is on, and enter the number on the keypad while holding down the “ALT” key.
Mac users: sorry — no lowercase 8, unless you know some undocumented way to insert the S-caron character