It shall not be necessary in a non-jury trial to resummon the witnesses or to hear them anew at a new trial if their testimony has once been reduced to writing, but all such testimony and evidence received on the former trial shall be considered as already in evidence. Any party may call new witnesses or offer additional evidence, and with the permission of the court recall any witness for further examination or cross-examination as the case may be. However, the parties shall not be precluded from producing new proofs, on the ground they have not been offered on the first trial. When a new trial is granted for reargument only, no evidence shall be adduced.