>Another transportation mode which existed in the Middle East was the Trans-Arabian pipeline....
As wiki points out, TAP kept running until 1976. Technology changed with supertankers, so Saudi decided to stop haggling over fees and not use it. Same thing for ME rail routes - they all required investment, and most ME countries had different priorities.
>My understanding is that TAP's significance ended largely with the 1967 war, though I'm not especially familiar with it.
The TAP stopped most operations because Saudi discovered they can use supertankers through international waters and pay much less in pipeline fees. The 1967 war may have actually given TAP a few years more - it closed the Suez canal for awhile, so tankers had to go the long way around. Suez reopened in June 1975 and soon after the Saudis stopped using TAP.
>Its existence does explain much of the strategic significance of Beruit (the pipeline's Mediterranean terminus) however.
TAP's terminus was at Sidon. As for Beirut, it was strategic for a different reason: The British Empire developed Haifa as a big Med port, but Arab state could not use it after Israel was founded; Beirut was the alternative for Haifa they could use.
As wiki points out, TAP kept running until 1976. Technology changed with supertankers, so Saudi decided to stop haggling over fees and not use it. Same thing for ME rail routes - they all required investment, and most ME countries had different priorities.