The existence of direct trains doesn’t preclude OSIs, examples include Euston (NR) to St Pancras (NR) or Aldgate to Aldgate East.
Some navigation software, like Google Maps, recommend walking Earl’s Court and West Brompton for the purpose of changing between District and Mildmay lines.
https://www.google.com.hk/maps/dir/Turnham+Green,+Chiswick,+London+W4+1QN/Clapham+Junction+Station,+Clapham+Junction/@51.4782413,-0.2633682,13z/am=t/data=!3m1!4b1!4m21!4m20!1m5!1m1!1s0x48760e3f1480c889:0x64c03a3daa0d97aa!2m2!1d-0.2544554!2d51.4951856!1m5!1m1!1s0x4876059bd2778d13:0x5784b843fc8df24d!2m2!1d-0.169492!2d51.4646378!2m5!5e1!5e2!6e0!7e2!8j1777053600!3e3!5i3?entry=ttu&g_ep=EgoyMDI2MDQxNS4wIKXMDSoASAFQAw%3D%3D
However, Citymapper thinks that taking the one-stop tube will arrive 9 minutes faster than walking it because it thinks that a 1-minute connection between opposite directions at Earl’s Court is possible, which, in my opinion, is a bit dodgy.
https://citymapper.com/trip/signature?signature=eJydlUtP4zAQx79KlMsetgG%2F4iTceFS7Yh8g6IoDQpEVu623qd11nC0I8d3XTlpat0WgvVS1xzPzn9844%2Be4YiY%2BiSDANB1EMW8Ns1Irt4VIQdyOUNwtnmPGuRFN4%2F7HZ8KOjeCD6JZJZaNLPVWfmuhGM7f1XSuu1SD69S12zpXWhnc%2BKTwiFBYkHyTgCNIMk8wfUGwuvPm8Zospm0eXraq6%2FC%2FO%2BNuUUnHx6A4At6zFxIe6f465bCxTlffEBIeycUq96mqdtCAY%2BZyIZhnyKaUqnffqdAyOKfC7c807IUtWz%2Fy62QRAMO8D0F6z1aV4lLaTPZXNUlaza2Zm5RAVaeaFO4FiwYxtHTAvmOTgIRSZ5eAVbTxkpm7OdWusjz4VjC%2FZkzOkWb4lzBqmGtkdMbq1opQd2Pv4wsEwsrKxz%2BEqM3vKunqsXpSVbpW35uuNdYzrmtmxNvMyKOii5EPv%2B2rdKO1tD32xm26kRVgnBWEvepKwwGm63wr4fiu2%2FQ%2BAhhjtkqZboO9EY8%2BMni%2BsMwWoUYH%2FH3XYvwA0ehN0iPIuwLyt01tv90GDsMo85JxniPag0pQcAp2%2FAzoMcIg03SNN0Bbq1ff8%2BjkHtDPwIdo%2FZM3nziGAvdvDADd%2BE3eA9CqgvSO1vCr5z7sDV5vAnXpTEkB30w2vhlt3uccu3WZQ7CQZjvRS7XcGHSPyTmuom5x9mrxw08bDWbg7KcqF6IUi7PtgxGQVs50ldTeU14SlmpRG%2FGkdEgfKHyGYVTTFJBmLAiYEZkWSE1AkAFBRkQxVDOTxVheC12A9MqKvcjL9wCtQIIBX8xTD4BEYtUb5R%2BCLEaJ%2FAazsLQggmgCSIDSCxQkCJwB8BtD9Hl8Mr09vRuXpyAf6K0zTV52%2B%2FANm%2BgQF
It wouldn’t matter if my Oyster card has capped for zones 1-2 or zones 1-3 on that day though, but it matters otherwise. Also, there is another cheap route which is surprisingly fast to travel from Ravenscourt Park back home, i.e. Ravenscourt Park – Richmond – Clapham Junction – East Croydon. I am surprised that despite looking circuitous on a map, travelling through zones 2-3-4-3-2-3-4-5, its total time is just a few minutes longer than via Victoria and saves about 10 minutes compared to changing at Earl’s Court / West Brompton / Clapham Junction. Why is the route via Richmond so fast?
