The 1033 transformer should have no problem powering your 2018 and tender. It should also blow the whistle quite loudly, provided (1) the whistle rectifier disc in the 1033 is good, and (2) the whistle in the tender is in good shape - specifically the motor. It may need to be serviced with a good cleaning and oiling of the bearings.

Clean the loco motor and wheels with naphtha, and lubricate the armature bearings with a light hobby oil. Use a hobby grease on the gears.
http://pictures.olsenstoy.com/cd/locos%5Cdebpix05.pdf

Clean and lube the whistle tender and its motor in a similar fashion.
http://pictures.olsenstoy.com/cd/locos%5Clen6026a.pdf

When all is cleaned and lubed, the 1033 should run the loco and tender with power to  spare. If it does not, there may be a problem with the transformer.

The tender whistle should blow loudly also. If not, the whistle rectifier disc may need replacement in the transformer.

Larry