Esseltub (sometimes called Esseltube) is the name of a typeface family formerly used in the Stockholm Metro. It was designed by Stig-àke Möller and was originally called SS-grotesk and SL-grotesk before being digitalised by Bo Berndal.
Prior to being replaced by Helvetica in the 1980s with black and white signs and later by Veolia Transport using a font called SL Nova, it was used on signs at the Stockholm Metro.