summon FallingSand ~ ~3 ~ {Block:redstone_block,Time:1,Passengers:[{id:FallingSand,Block:activator_rail,Time:1,Passengers:[{id:MinecartCommandBlock,Command:setblock ~1 ~-2 ~ command_block 3  {auto:1,TrackOutput:0b,Command:say Hello World!}},{id:MinecartCommandBlock,Command:setblock ~1 ~-2 ~1 repeating_command_block 3  {auto:1,TrackOutput:0b,Command:/say 1}},{id:MinecartCommandBlock,Command:"/tellraw @a {\"text\":\"\\\"Sample Project\\\" has been successfully installed!\",\"color\":\"green\"}"},{id:MinecartCommandBlock,Command:setblock ~ ~1 ~ command_block 0  {auto:1b,Command:fill ~ ~-3 ~ ~ ~ ~ air}},{id:MinecartCommandBlock,Command:kill @e[type=MinecartCommandBlock,dx=0]}]}]}