a and 52 b 0108 fig1 illustrates another shoring panel 5 having a magnetic connection with linear and or corner rail post by incorporating magnetic flat bars 54 on the sides of the panel guide 41 to prevent damage to the magnetic flat bars two plates 53 are fixed on the guide 41 to support the pressure of contact between post and panel as shown in the fig1 a sliding device 55 may be fixed to rail post 1 by bolts through holes 54 a and 54 b and into holes in the back side of the rail post this is desirable when the depth of excavation is great and there is a need to slide a pair of rail posts together the sliding device 55 has a formlocking t shaped piece 53 that goes inside the u2018 c u2019 channel in front of the other rail post identical to the u2018 t u2019 shaped piece 20 of the articulated frame shown in fig2 as shown in fig1 the truss supporting the twin pairs of rail posts acts simultaneously on the upper pair of rail posts 1 a and 1 b through the rollers 21 a 21 b and on the lower pair of rail posts 1 c and 1 d via the rollers 21 c 21 d the truss could be an articulated type as indicated schematically by the dash dot line or as a rectangular frame 0111 fig1 shows another accessory device to be fixed on the top of the panel 5 to prevent damages during the installation of the system the accessory device is made by welding together the two plates 57 and 58 the device can be pinned.