The merger you are reffering to has yet to happen.
Just to clear up something. When the MTA talked of creating this new "MTA Railroad" from LIRR and MNCR, it is not to be confused with a Penn Central type of merger, where both lost their identity. The LIRR and MNCR were to retain there corporate names and MTA Railroad was well, to be a Department within the MTA acting somewhat like a holding company that would administer and manage the railroads. All the administrative functions of both roads would be in this MTA Railroad.
It isn't new to the LIRR. Under the Pennsy era, it wasn't uncommon for the President of the PRR to be the President of the LIRR too. And have certain administrative functions to be handled in Philadelphia instead of Jamaica.
Already within the MTA, some of the administrative functions have already been merged between LIRR and MNCR and have been for years.
Considering that LIRR and MNCR have separate Presidents and managements, merging these positions under a new umbrella entity like MTA Railroad might be considered a merger of the roads but it's not in the traditional sense that we would consider a merger. Besides, the MTA already stated that each road was to retain it's name and that they were conscious of the fact that the LIRR is the oldest railroad in the U.S. that is operating under it's original name and it will remain so.
By the way guys come on. The LIRR hasn't closed shop since April 24, 1834. Even during a strike it isn't uncommon for management to move equipment around or do something there. We can all play Corporate Geneology and say who is older. Maybe I'll open up a corporation and call it Baltimore & Ohio RR. Then I can claim my railroad is older. But it wouldn't be because no railroad in the U.S., including Strasburg by the way, has run some sort of rolling stock EVERY SINGLE DAY without interuption since 1834, under the same corporate name, except for the LIRR. When Strasburg went from a paper railroad to an operating and fully functional railroad, the LIRR was already well established.