Abstract: This circular saw blade has a center disk and circumferential teeth segments secured to the center disk, for example, by welding. The center disk has two rows of circumferentially spaced radially outwardly extending lands. The two rows of lands are preferably axially spaced from each other by a circumferential groove. The lands in each row are circumferentially spaced by gaps, whereby the lands in one row are angularly displaced relative to the lands in the other row so that the lands in one row face the gaps in the other row. The teeth segments are provided with the same type of lands and gaps, but facing radially inwardly, whereby the lands contacting each other on both sides of the disk may be electronically welded from one side of the disk. Worn out segments may be easily removed by a cutting or grinding tool having an outer diameter somewhat smaller than the distance from one outer wall of a gap to the outer wall of the next adjacent gap.

Abstract: A roadway for rapid transit railways comprises concrete or reinforced concrete piers supporting an all steel support or suspension structure for the support and/or suspension as well as guiding of the vehicles.