The double account system is an accounting method used by public utilities like railways and utilities to present annual financial statements. It separates capital/fixed assets and current/working assets into two accounts. The capital account tracks fixed assets, liabilities, and capital expenditures. The general balance sheet tracks current assets, liabilities, the revenue account, and net revenue account. Key features include showing depreciation as a liability, treating discounts/premiums as capital, and charging interest to the net revenue account. Advantages include easier asset replacement and government oversight of costs/service. Disadvantages include assets not shown at written-down value and difficulty distinguishing capital vs revenue expenditures.