N1837M is seen patiently awaiting the fueltruck at Kenai. The co-pilot saw to the refuelling, while the captain was evaluating the weather for his next destination.

For the history of N1837M see the details as described on my visit to Fairbanks in 2003,

N37570 was converted to DC-6B(F) for carrying freight in Dec.1974.
In a few months it found a new operator: St Lucia Airways leased it as VQ-LAW from Feb75; in november it was returned to Mark Aero and registered N37570 again. Edwin R Phelps Jr bought N37370 that month. Petroleum Air Transport leased if from feb78 to Mar80.
ircraft Leasing Corporation became the new owner in Jan81, but it may have been stored without much use at Fort Lauderdale,FL for a long while.
And then Carolina Aircraft Corporation decided to buy it in May86; but Florida Aircraft Leasing Corporation seems to have it returned (or bought it again) in Apr86.
Its historic tailnumber was about to change to N990CA (for Florida Aircraft Leasing Corporation or a client), but this fell thru.
the tailnumber did change though: it became HR-AKW for Servicios Aereos Generales upon a sale in Dec. 1986. But did it actually go to Honduras? because it was changed back again to N37570 for Bauford Marine Services Inc in July 1988...
A year later, in May 1989, Air Taxi International Inc bought N37570. ILPO Cargo Airlines leased it from May89 and it was consequently registered as XA-RMM for ILPO (in Jun90). The lease was terminated in Sep90.
Regal Air leased it from Air Taxi in/from Sep91; and Legion Express Inc did the same in/from Nov96.
5Y-BMM became a new exotic tailnumber, for Sincereways (purchase Sep97). But again it may have stood around mostly, waiting, without much use at Opa Locka,FL.
And then the present owner bought N37570, in August 1998. On 09Oct98 it was reregistered N600UA for Universal Airlines. And long may she fly and earn her daily bread !!

UPDATE!!! John Maxwell sent me a photo, in June 2011, of N600UA involved in a wheels-up landing at Cold Bay HERE.. Will the cost of the repairs mean the end of this classic, sturdy skytruck?!

N500UA and on the left, in the distance, another Universal DC-6 (which I did not pursue, N170UA?) .

N500UA is a Douglas C-118A (c/n 44597, linenumber 501). It was delivered with tailnumber 53-3226 to the United States Air Force on 27Aug54; after its career with the Air Force, it was handed over to the boys in blue: as 153691 it went to the United States Navy on 15Jun65.
Its military career ended (I don't know the date) in the desert: the storage yard of Davis Monthan Air Force Base in Arizona.
Arctic Select Seafoods Inc bought it in march 1987 and registered it as N766WC; but the United States Customs Service saw cause to seize N766WC in Feb88.
Florida Aircraft Leasing Corporation became the next owner, in June 1990; Gulf & Caribbean Cargo leased it from March 1992, ending the lease in May 1997.
Aztec Capital Corporation purchased N766WC in Oct98, on a sale/lease back arrangement with Florida Air Transport. This lasted only until May 1999.
Present owner, Universal Airlines, bought this DC-6 that same month: May99. And N500UA became its new tailnumber for Universal Airlines on 07Jul99.
UPDATE 2022: on my report USA 2012!

I had hoped to be able to visit this company on its base at Statesville Municipal Airport,NC during 2005 but found they had moved to Victoria,TX. I was glad I got to most of their planes here at Kenai.
On my 'general' Alaska 2006 page there is another N500UA photo, getting some maintenance.

N170UA was reg'd to Tatonduk Outfitters of Fairbanks,AK on 23Oct2015. The same for another Universal AL SIX, N500UA, reg'd on that same date.