Hurray! Someone posted here. Thanks, Vicky, for not letting this thread die out in one day.

I'll post my thoughts now, in case there remains little interest I'd like to spout my opinion on the matter.

For starters, south Korea paid the DPRK an 80 million dollar bribe for their military to "permit" this
one time test run. That doesn't include the 150+ million dollars worth of foodstuffs and goods it also promised for this one-time run. I'm reminded of the $500 million dollars worth of bribes paid by the Kim Dae-jung government to secure the world's most expensive photo op with Kim Jong-il at the June 2000 Inter-Korean summit. If the south keeps this up the north won't need such a robust counterfeiting ring.
This is touted as a step towards reunification, but the main reason that the ROK government wants the rail link to work is not because of reunification. They hope that the link will enable them to realize their dream of being the
logistic hub of NE Asia, potentially offering the ROK a great deal of money and prestige. If the DPRK were to hypothetically keep the link open, a container train from Europe could go all the way to Busan via the TSR. Transporters would find that a lot cheaper then shipping containers via huge ocean going ships as they do now. All of that is good.
The down side: The DPRK government could make a ton of money just allowing container trains to run non-stop through heavily fenced off and guarded rail lines in DPRK. That money would go into the DPRK coffers and directly finance the most authoritarian government in the world.
Case in point, what has happened since the Gaeseong industrial park opened, with billions financed by the ROK government? KJI kicked out the world food agencies, and finished development of his nuclear weapons program. It doesn't take a psychic to forsee this ‘deal’ continuing to cost the ROK incredible amounts of cash to KJI to ensure that the route remains open and ‘free’. Future ‘accidents’ or ‘breakdowns’ and urgent calls for billions to fix a broken rail track, “train hits cow/bus/schoolboy, send X hundred million in cash immediately or the trains will be delayed for a few weeks”.