Based on the provided legal document, here are the key points extracted with their respective references:

Case Details and Parties * The case is an intra-Court appeal filed by Delhi Metro Rail Corporation Ltd. (DMRC) against Delhi Airport Metro Express Private Limited (DAMEPL). (!) * DMRC is a state-owned company with equal participation from the Government of India and the Government of National Capital Territory of Delhi. (!) * DAMEPL is a special purpose vehicle incorporated by a consortium of M/s Reliance Infrastructure Limited and M/s Construcciones Y Auxiliar de Ferrocarriles SA. (!) * The dispute relates to the Concession Agreement (CA) signed on 25th August, 2008, for the construction, operation, and maintenance of the Delhi Airport Metro Express Line (AMEL). (!)

Background and Timeline of Events * DMRC undertook land acquisition and civil structures, while DAMEPL was responsible for railway systems, rolling stock, and signaling. (!) * DAMEPL was entitled to collect fares and non-fare revenue, and was required to pay an annual concessionaire fee of Rs.51 crores. (!) * DAMEPL paid the concessionaire fee for the first year but stopped subsequent payments, requesting deferment due to financial constraints and lack of retail revenue. (!) * On 8th July, 2012, DAMEPL stopped operations citing unsafe conditions regarding viaduct bearings and girders. (!) * DAMEPL issued a cure notice on 9th July, 2012, and subsequently a termination notice on 8th October, 2012, under Article 29.5.1 of the CA. (!) * Repairs were undertaken, and on 18th January, 2013, the Commissioner of Metro Road Safety (CMRS) granted sanction to restart operations with speed restrictions. (!) * DAMEPL resumed operations on 22nd January, 2013, and handed over the project to DMRC on 30th June, 2013. (!) * An Arbitral Tribunal was constituted on 8th August, 2013, and pronounced its award on 11th May, 2017. (!)

Arbitral Award Findings * The Arbitral Tribunal held that there were defects in the civil structure (cracks, twists, gaps) which were not cured within the 90-day period specified in the cure notice. (!) * The Tribunal found that these defects had a "Material Adverse Effect" on DAMEPL's ability to perform obligations, validating the termination notice under Article 29.5.1. (!) * The Tribunal held that DAMEPL's participation in meetings and operations after the termination notice was "without prejudice" to their rights and did not amount to a waiver. (!) * The Award directed DMRC to pay DAMEPL a termination payment of Rs.2782.33 crores, comprising debt due and 130% of adjusted equity. (!) * The Tribunal included Rs.611.95 crores as part of the "adjusted equity" despite DAMEPL's balance sheets categorizing it as subordinate debt. (!)

High Court Judgment (Appeal) * The High Court set aside the findings regarding the validity of the termination notice due to confusion and contradiction in the Award regarding the date of termination (8th October, 2012 vs. 7th January, 2013). (!) * The Court held that the Award suffered from perversity and patent illegality for ignoring the statutory sanction granted by CMRS on 18th January, 2013, which certified the safety of the line. (!) * The Court set aside the finding that Rs.611.95 crores should be treated as equity, ruling it perverse to ignore the Board resolution converting share application money into subordinate debt. (!) * Consequently, the direction to pay interest under Article 29.8 on the termination payment was held infructuous. (!) * The Court set aside the Award in its entirety regarding the termination payment and consequential reliefs, leaving the matter for fresh adjudication via arbitration. (!) * The Court upheld the finding that DAMEPL did not waive the termination notice by election or conduct. (!)