Train Leaves Here This Morning by Bernie Leadon and Gene Clark, 1968.

Blue Heaven practicing on a warm Sunday afternoon, 12/03/23.
From Songfacts: " This is a melancholy song about the end of a marriage. Bernie Leadon waxes bitterly about the breakdown of their relationship after they'd signed a contract for life. Now he plans to escape his romantic travails and head home on the morning train.
Bernie Leadon wrote "Train Leaves Here This Morning" with the original lead singer of The Byrds, Gene Clark. Leadon and Clark's then-group, Dillard & Clark, recorded the original version for their 1968 The Fantastic Expedition of Dillard & Clark album.
A major difference from Dillard and Clark version is Glen Frey's electric guitar solo, "The Eagles rendition is very country, folky and stripped-down," Leadon told Uncut magazine. "There's electric lead, electric bass and drums, but they're lightly played. Its singer-songwriter type, stripped-down production and vocal orientated."
The Eagles recorded their twangy version for their self-titled debut album. Produced by Glyn Johns, famous for his work with Led Zeppelin, The Who and The Rolling Stones, they laid the tracks down at Olympic Studios in London. "I brought them to England, and we made the album very quickly in under three weeks," Johns remembered. "I don't think I'd been as excited since probably Led Zeppelin - they were amazing but they didn't really know what they'd got. "