Well if you want to go in-depth, Lionel and the LCCA got taken to the woodshed with New Haven 'Merchants Limited' set. This was the first re-issue of the 'conventional classics' style Alco, from the rare 1958 set. It has a powered rear truck like the postwar version and later MPC ( 1970-80 ) Alco engines. The locomotive could barely pull the set. When the add-on B unit and cars became available, forget it. The engine wheels would just spin. I have the original and LCCA re-issue sets. I placed the 1958 locomotive in front of the set and it walked away with the set. What was the problem? I found out by playing around with both sets that the Magne-traction on the LCCA re-issue was very weak compared to the originals. Cheap Chinese magnets. The way I corrected my problem was I has a spare 2 axle magne-traction truck from a broken common 218 Santa Fe Alco. It was a very easy swap of trucks as the re-issues are the same mounting as the original. Now the original and re-issue New Havens pull equal.
Operators were (are) very disappointed with this set. If you go to Lionel's parts break down of the New Haven Alco, you will find this the only re-issue of this style of engine with the motor in the rear, all the ones fallowing are front truck drive. They have now added traction tires to the wheels along with a slightly improved Magne-Traction. The 209 NH did not have tires. I Asked Mike Regan years ago why Lionel changed from rear truck to front truck? Pulls better was his reply. Why couldn't they just make the magnets more powerful instead of changing the whole set-up? His reply was something to effect of 'That's just the way Lionel does thing now' Probably a pre-curser of Chinese manufacturing to come. (My comment).
So the OP's Alaska engines have the front truck motor with traction-tire wheels and Magne traction. Be sure the traction tires are fairly fresh and not glazed from running a lot.
So that is the story that got a lot of LCCA members back in 2009 PO'ed at Lionel for not making good on repairing the traction problem. I remember several 209 engines brought to me saying the engines were broken because they didn't pull the original passenger set.