Updated: May 12, 2021
| Unit | Formation | Delivered | Factory | Notes |
| Class 777 - 53 units | ||||
| 777001 | 427001-428001-429001-430001 | 05/01/21* (13) | Siedlce | Undergoing testing |
| 777002 | 427002-428002-429002-430002 | 06/05/21 (14) | Altenrhein | Undergoing testing |
| 777003 | 427003-428003-429003-430003 | 16/01/20 (1) | Siedlce | Undergoing testing |
| 777004 | 427004-428004-429004-430004 | 13/05/20 (2) | Altenrhein | Undergoing testing |
| 777005 | 427005-428005-429005-430005 | 09/07/20 (4) | Siedlce | Undergoing testing |
| 777006 | 427006-428006-429006-430006 | 28/07/20 (6) | Altenrhein | Undergoing testing |
| 777007 | 427007-428007-429007-430007 | 21/05/20 (3) | Siedlce | Undergoing testing |
| 777008 | 427008-428008-429008-430008 | 20/08/20 (7) | Altenrhein | Undergoing testing |
| 777009 | 427009-428009-429009-430009 | 09/07/20 (5) | Siedlce | Undergoing testing |
| 777010 | 427010-428010-429010-430010 | 20/08/20 (8) | Altenrhein | Undergoing testing |
| 777011 | 427011-428011-429011-430011 | - | Siedlce | Completed, stored at Siedlce |
| 777012 | 427012-428012-429012-430012 | 22/10/20 (9) | Altenrhein | Undergoing testing |
| 777013 | 427013-428013-429013-430013 | - | Siedlce | Not built |
| 777014 | 427014-428014-429014-430014 | 22/10/20 (10) | Altenrhein | Undergoing testing |
| 777015 | 427015-428015-429015-430015 | - | Siedlce | Completed, stored at Siedlce |
| 777016 | 427016-428016-429016-430016 | 16/12/20 (11) | Altenrhein | Undergoing testing |
| 777017 | 427017-428017-429017-430017 | - | Siedlce | Not built |
| 777018 | 427018-428018-429018-430018 | 16/12/20 (12) | Altenrhein | Undergoing testing |
| 777019 | 427019-428019-429019-430019 | - | Siedlce | Not built |
| 777020 | 427020-428020-429020-430020 | - | Altenrhein | Not built |
| 777021 | 427021-428021-429021-430021 | - | Siedlce | Not built |
| 777022 | 427022-428022-429022-430022 | - | Altenrhein | Not built |
| 777023 | 427023-428023-429023-430023 | - | Siedlce | Not built |
| 777024 | 427024-428024-429024-430024 | - | Altenrhein | Not built |
| 777025 | 427025-428025-429025-430025 | - | Siedlce | Not built |
| 777026 | 427026-428026-429026-430026 | - | Altenrhein | Not built |
| 777027 | 427027-428027-429027-430027 | - | Siedlce | Not built |
| 777028 | 427028-428028-429028-430028 | - | Altenrhein | Not built |
| 777029 | 427029-428029-429029-430029 | - | Siedlce | Not built |
| 777030 | 427030-428030-429030-430030 | - | Altenrhein | Not built |
| 777031 | 427031-428031-429031-430031 | - | Siedlce | Not built |
| 777032 | 427032-428032-429032-430032 | - | Altenrhein | Not built |
| 777033 | 427033-428033-429033-430033 | - | Siedlce | Not built |
| 777034 | 427034-428034-429034-430034 | - | Altenrhein | Not built |
| 777035 | 427035-428035-429035-430035 | - | Siedlce | Not built |
| 777036 | 427036-428036-429036-430036 | - | Altenrhein | Not built |
| 777037 | 427037-428037-429037-430037 | - | Siedlce | Not built |
| 777038 | 427038-428038-429038-430038 | - | Altenrhein | Not built |
| 777039 | 427039-428039-429039-430039 | - | Siedlce | Not built |
| 777040 | 427040-428040-429040-430040 | - | Altenrhein | Not built |
| 777041 | 427041-428041-429041-430041 | - | Siedlce | Not built |
| 777042 | 427042-428042-429042-430042 | - | Altenrhein | Not built |
| 777043 | 427043-428043-429043-430043 | - | Siedlce | Not built |
| 777044 | 427044-428044-429044-430044 | - | Altenrhein | Not built |
| 777045 | 427045-428045-429045-430045 | - | Siedlce | Not built |
| 777046 | 427046-428046-429046-430046 | - | Altenrhein | Not built |
| 777047 | 427047-428047-429047-430047 | - | Siedlce | Not built |
| 777048 | 427048-428048-429048-430048 | - | Altenrhein | Not built |
| 777049 | 427049-428049-429049-430049 | - | Siedlce | Not built |
| 777050 | 427050-428050-429050-430050 | - | Altenrhein | Not built |
| 777051 | 427051-428051-429051-430051 | - | Siedlce | Not built |
| 777052 | 427052-428052-429052-430052 | - | Altenrhein | Not built |
| 777053 | 427053-428053-429053-430053 | - | Siedlce | Not built |
* - Delivered to Crewe on 16/12/2020, transferred to Kirkdale TMD on 05/01/2021.
