4. The introductory facts, in brief, are as follows: - ‘The General Manager, Central Organisation for Railway Electrification [Core], Allahabad i.e., the 1st petitioner had issued a tender for construction of electric loco shed and doing ancillary works, for the estimated value of Rs.2,45,11,415.45ps. For the said offer, the claimant firm had issued a letter of acceptance on 03.06.1991. After the claimant firm had furnished a bank guarantee dated 15.06.1991, the agreement was finalised and was entered into on 07.10.1991. After furnishing the bank guarantee for Rs.24.50 Lakhs, the mobilization advance in a sum of Rs.24,49,992/was disbursed. The said advance is to carry interest @ 10% per annum as per clause 24 of the agreement and is to be repaid by 02.06.1993. The claimant firm having executed the work of the value of Rs.76.93 Lakhs had sought for the increase of 80% of the contractual rates by way of a letter dated 02.06.1993, which is the date for the completion of the contracted work. The claimant firm had by a letter dated 03.04.1993 sought extension of the contract up to 02.08.1993. The said extension was given under clause 17(3) of the General Conditions of Contract (‘the GCC’ for short) without levy of liquidated damages. The claimant firm by