Can Department sign the Dismissal Order of his workmen? As per disciplinary proceedings of Model Standing Orders?

In fact, the CSO has to contain details of the Appointing Authority, Disciplinary Authority for minor punishment, Disciplinary Authority for major punishments and the Appelate Authority for each class of employees, as per the delegated authority of the Executives of the organisation. If that is not included the CSO can be treated as incomplete. Transparency is a must in such type of establishment matters.

Sir if I understood correctly.. Company Secretary office will have delegation of power & authority's approved by board.
GM-HRD communications & signature are legally valid but,the delegation details are not disclosed by company
Will you please advice, how to take the case to court with out knowing the delegation of powers.
Tnx

Delegations are distinct for each class of executives, not common for all on all the issues. Company Secretary is usually delegated with legal and secretarial powers plus adequate financial pwers for his own department.
Delegation for administrative and disciplinary powers are open for all to note, cannot be kept as a secret weapon by any department. You may check with the HR department of your organisation.