With a slowing construction market, speculation has become the favourite past time of firms based in Abu Dhabi.

So when Etihad Rail decided to drop the link to Oman from the retendered second phase of the federal rail network it was hardly surprising that within days there were a wide array of theories purporting to explain why.

Some explanations are practical. With oil prices are still depressed, Abu Dhabi is seeking to reduce its capital expenditure on new projects, and the link to Al-Ain and the Oman border is one of the projects the authorities felt that for now they could do without.

Phasing is another of the more practical explanations. With Abu Dhabi waiting to see if Oman moves ahead with its connection that will run from Sohar to Buraimi and connecting to the UAE at Al-Ain.

While practicalities could well be the reason, the most popular explanations have been political.

The first centres on trade and competition. Oman has ports, notably Sohar and Duqm, that are outside the Straits of Hormuz. At present these ports are relatively remote for the main GCC markets of the UAE and Saudi Arabia, but they could be major competition for Jebel Ali Port in Dubai and Khalifa Port in Abu Dhabi if a rail link is built connecting to the rest of the GCC.

The second explanation comes from foreign policy. In recent months, Oman’s position on issues such as Iran and military intervention in Yemen has differed from the more hawkish stance adopted by the UAE and Saudi Arabia, and some say this is the cause for the rail link being dropped.

Whatever the reason, the speculation could be quashed if the UAE reveals what its future plans for the link to Al-Ain and Oman are. Until that happens, the intrigue will continue.