A bearing between planar guide surfaces (45', 45") of a guide rail pillar of a mould box and a mould plate of the mould box, the mould plate being moveably arranged on the guide rail, the guide rail having a longitudinal axis, the bearing comprising a bearing element, wherein the bearing element has a main body part with a first end and a second end and a through-going opening for receiving said guide rail pillar, the through-going opening extending from said first end to said second end through said body part, and the through-going opening having one inner surface (151', 151", 152', 152") for each planar guide surface (45'.45") of the guide rail pillar, characterized in that, for at least one of the guide surfaces (45', 45") of the guide rail pillar, the bearing element comprises a first planar bearing surface and a second planar bearing surface arranged in a common plane (P 1) and parallel to the planar guide surface (45', 45"), and spaced apart in the direction of the longitudinal axis, the first bearing surface arranged at the first end and the second bearing surface arranged at the second end of the bearing element, wherein the first and second bearing surfaces (64, 65) are elevated above the corresponding inner surface (151', 151", 152', 152") of the through-going opening, wherein the first and second bearing surfaces (64, 65) are separated by an intermediary surface portion being retracted from the common plane (P 1) of the two bearing surfaces (64, 65), and wherein, below each of the first and second bearing surfaces (64, 65), a cavity (74, 75; 74', 75'; 174, 175) is formed in the bearing element, such that a portion (84, 85) of the bearing element is provided with a resilience relative to the main body part of the bearing element. wherein the bearing element has a main body part with a first end and a second end and a through-going opening for receiving said guide rail pillar, the through-going opening extending from said first end to said second end through said body part, and the through-going opening having one inner surface (151', 151", 152', 152") for each planar guide surface (45'.45") of the guide rail pillar, characterized in that, for at least one of the guide surfaces (45', 45") of the guide rail pillar, the bearing element comprises a first planar bearing surface and a second planar bearing surface arranged in a common plane (P 1) and parallel to the planar guide surface (45', 45"), and spaced apart in the direction of the longitudinal axis, the first bearing surface arranged at the first end and the second bearing surface arranged at the second end of the bearing element, wherein the first and second bearing surfaces (64, 65) are elevated above the corresponding inner surface (151', 151", 152', 152") of the through-going opening, wherein the first and second bearing surfaces (64, 65) are separated by an intermediary surface portion being retracted from the common plane (P 1) of the two bearing surfaces (64, 65), and wherein, below each of the first and second bearing surfaces (64, 65), a cavity (74, 75; 74', 75'; 174, 175) is formed in the bearing element, such that a portion (84, 85) of the bearing element is provided with a resilience relative to the main body part of the bearing element.