I'm not sure, if I understand your circuit correct, but it sounds wrong, like a series connection of windings. You definitely need a parallel circuit of all four transformers.
Following an usual (in power electrics) designation of terminals:
U1 and V1 are the primary terminals of transformer 1, u1 and v1 the secondary terminals and so on. Then you have to connect U1 with U2,U3,U4 and V1 with 2,V3,V4 for the primary (input) side, similar at the secondary side. This is cause a parallel circuit keeps the voltage at each transformer but sums the currents.
Most likely the terminals can't connect more than 1 or 2 wires with sufficient cross section for 50 A. In this case you would need additional terminal strips to connect the feed lines of each transformer. If the transformers are equipped with stay bolt terminals, it may be possible to do the parallel connection without additional terminal strips. I assume that you are able to calculate the cable cross sections in each case.
Paralleling transformers is very common in power distribution networks. However, some conditions must be met to allow it without unwanted cross-currents and to achieve equal load distribution. Using transformers of equal type is always O. K., so I skip discussing the general conditions in detail.
It may be regarded necessary to use individual overload protections for each transformer. This would be surely done with high power transformers. Overload could happen, e. g. if the connection of an individual transformer is loose. A small voltage drop could result in nearly no load caried by this transformer, possibly overloading the others.