Following his appointment Valtanen informed the other members of the committee that the plans made under Castrén leadership were outdated, and now the metro would be planned as a heavy rail system in deep tunnels mined into bedrock.
Då Valtanen utsågs meddelade han de övriga medlemmarna i kommittén att planerna som gjorts under Castréns ledarskap var gammalmodiga och att metron nu skulle planeras som tung spårtrafik med tunnlar som borras djupt in i berggrunden.