But these electric cranes must be introduced in a worldwide scale, every major port must introduce them. andit's not onlny electric cranes, it's also ships that allow for efficient handling of containers via cranes. It's lorries and trains able to transport containers from the ports and to the ports - I mean, what's the purpose of everything being transported to ports, packed by hands into containers, packed into (new) ships by cranes sipped to (selected) ports able to unload the containers and then have them unpacked again by hand in the port?
Container transport suffers/gains from network effects, that is you require a huge amount of money invested in infrastructure to have a huge ntwork able to handle containered transportation, then the network will expand pretty much by itself as anyone participating will profit. The problem is the huge initial cost. And in case of Italy, the additional probem is that an international network is required.
However, what could easily be done is establishment of a containerized supply line for Libya.
A lot may depend on how efficient the Italian system appears to work...which given Fascist Italy's OTL record on efficiency could be an issue.
I suspect that, at least for some loads, smaller containers would be in order. 1920's trucks likely wouldn't like modern containers from OTL--too big. Of course, most heavy cargo transport is by rail, so big might work--but would make it less useful for military logistics away from the railhead.
I can easily see pallets one flatcar long, with several truck sized containers for areas with no rail easily available. Roll the train to the railhead, then off load the smaller containers onto trucks.
That might not be necessary for civilian use--almost every industry back then had a railroad siding.
This idea was developed and put into use by the Pennsylvania RR in 1929 or so. the Interstate Commerce Comission decided that it was anti-compettitive and killed it in the very early 30's. It takes more than the idea sometimes you need a government that supports it.
The article also notes that the UK was using containers even earlier than your PoD