A railway axle-box including a system for measuring the temperature of a rolling bearing comprised in the railway axle-box; wherein the temperature measuring system comprises: - a first hole made in radial direction with respect to a symmetry axis of the bearing externally on a cover of the railway axle-box on the side of an edge of the cover facing towards the rolling bearing; - a second hole having smaller diameter than the first hole and made in axial direction with respect to a symmetry axis of the bearing on the edge of the cover so as to be in use facing towards a ring of the bearing, said bearing cooperating in abutment against the edge of the cover, the second hole opening in the first hole; - a temperature probe (28; 28b) slidingly accommodated within the second hole and in turn comprising a tubular element longer than the second hole and carrying therein at least one electrical temperature sensor provided with an electrical connecting cable protruding from a first end of the tubular element; said railway axle-box being characterized in that said temperature measuring system further comprises: - a cup-shaped body accommodated in the first hole, said first end of said tubular element of said temperature probe (28, 28b) being overhangly accommodated within said cup-shaped body; - a spring integrally carried by the cup-shaped body, therein, so as to project in front of the second hole, which second hole is in direct communication with the interior of the cup-shaped body; - a shoulder element integrally coupled to the first end for cooperating with the spring; said railway axle-box being further characterized in that the length of the second hole and of the tubular element, the shape of the spring and a coupling position of the shoulder element with the tubular element are selected so that the spring pushes the probe (28;28b) towards an extracted position in which a second end of the tubular element axially protrudes out of the second hole, so that when the cover is arranged with the edge in abutment against the ring of the bearing, the spring is preloaded and presses the second end of the tubular element of the probe (28;28b) against the ring of the bearing. - a first hole made in radial direction with respect to a symmetry axis of the bearing externally on a cover of the railway axle-box on the side of an edge of the cover facing towards the rolling bearing; - a second hole having smaller diameter than the first hole and made in axial direction with respect to a symmetry axis of the bearing on the edge of the cover so as to be in use facing towards a ring of the bearing, said bearing cooperating in abutment against the edge of the cover, the second hole opening in the first hole; - a temperature probe (28; 28b) slidingly accommodated within the second hole and in turn comprising a tubular element longer than the second hole and carrying therein at least one electrical temperature sensor provided with an electrical connecting cable protruding from a first end of the tubular element; said railway axle-box being characterized in that said temperature measuring system further comprises: - a cup-shaped body accommodated in the first hole, said first end of said tubular element of said temperature probe (28, 28b) being overhangly accommodated within said cup-shaped body; - a spring integrally carried by the cup-shaped body, therein, so as to project in front of the second hole, which second hole is in direct communication with the interior of the cup-shaped body; - a shoulder element integrally coupled to the first end for cooperating with the spring; said railway axle-box being further characterized in that the length of the second hole and of the tubular element, the shape of the spring and a coupling position of the shoulder element with the tubular element are selected so that the spring pushes the probe (28;28b) towards an extracted position in which a second end of the tubular element axially protrudes out of the second hole, so that when the cover is arranged with the edge in abutment against the ring of the bearing, the spring is preloaded and presses the second end of the tubular element of the probe (28;28b) against the ring of the bearing.