Existing rail and water links between Iran and the Soviet Union could blunt any United States attempt to force the return of the American hostages by means of a blockade, in the opinion of transportation experts.
The fact is that Iran enjoys multiple avenues for importing its necessities -- most of them beyond US ability to interrupt.
Indeed, to many, an American blockade would offer the Soviet Union an unprecedented and gratuitous opportunity to gain legitimate entry into Iran, in the guise of supplier and protector of a third-world nation.
The Soviets could undercut any US blockade by providing alternative routes for Iran's import needs -- even though the Russian gambit does involve literally reversing the current traffic flows.
The bulk of Iran's imports now arrive in the port of Khorramshahr, near the southwestern oil fields, and move northward by rail and truck to Isfahan and the northern cities.
The Soviet option means rerouting railway rolling stock and trucks to move goods southward.This logistical change is a straightforward one in the sense that overall distances, especially for truck movements, actually are less.
The Soviet Union's trans-Caucasus railroad is the principal freight link between the two countries today. It parallels the Araxes River and connects with the Iranian state railways at Julfa. Facilities exist for switching from Russian broad-gauge rolling stock to the standard gauge used throughout Iran. This connection has functioned with increasing effectiveness in recent years to supplement seaborne imports into Iran.
Moreover, the 125-kilometer stretch from Julfa to the freight yards in Tabriz is short enough that the transshipment of goods between the two rail networks can be facilitated by trucks using the existing, solidly constructed military roads in the area.
An additional rail-truck route exists in Iran's northeast. This link depends on the Soviet Central Asian line. Trucks from Mashhad in Iran meet the Mary-to-Ashkhabad Soviet rail spur near the Soviet-Iranian border, and goods then can continue to or from the Soviet port of Krasnovodsk on the eastern shore of the Caspian Sea by rail.
Originally built to supply the conquering armies of the czars, the rail line also connects with the Afghan frontier at Kushka.
In both cases, off-loading onto trucks is necessary, but an excellent 400 -kilometer road connects Kushka with Mashhad, the center of population in eastern Iran and the terminus of the Iranian rail system.
As a third alternative, the Soviets have a well-developed system of barge traffic on the Volga River, which reaches deep into the Soviet industrial heartland. Barges can descend the Volga and discharge cargo into two existing Iranian Caspian Sea ports.
Bandar Khomeini (formerly Bandar Shah) is the northern railhead in Iran, so forwarding to Tehran is immediate. A second barge port, Enzeli (formerly Bandar Pahlavi), long the major port of entry into Iran, connects to Tehran via several heavy-duty roads across the Elburz Mountains.
These transport operations are considered routine in both countries. But the vulnerability of the rail link via Julfa to attack by guerrillas is a cause for concern. The route traverses rough, difficult terrain in which both Kurdish and Azeri Turkish nationalist bands have roamed recently, and it is close to the Iraqi frontier as well.
Beyond the three Soviet connections, Iran possesses two supplementary supply routes --Pakistan in the east.
A major road through Turkey connects Azerbaijan Province in northwestern Iran with Central and Eastern Europe.
The railroad link through Turkey -- ironically financed in part under the now-defunct, Western-oriented CENTO alliance -- is also serviceable, although part of the trackage traverses troubled Kurdistan.
The second backstop option is the Pakistani railroad that reaches from Karachi on the Indian Ocean, across Baluchistan to a railhead at Zahedan in southeastern Iran. Once isolated, Zahedan today is only 400 kilometers from the newly extended Iranian railroad near Bam.
This route necessitates double handling and an intermediate truck link, but it nevertheless could be used by Iran.
The Turkish and Pakistani alternatives may prove difficult to operate, but they would at least enable Iran to dilute somewhat its reliance on the Soviet Union.