If they rely on software or manual calculations without a standardised convention, they will end up with opposite signs for their voltage drops and power factors, leading to catastrophic equipment failure upon physical assembly. The IEC 60375 standard ensures that:

: Manufacturers must adhere to these conventions to pass regulatory testing and achieve international certification.

The standard establishes consistent graphical and notational conventions used in:

Legacy trains required massive, heavy bundles of point-to-point cables. TCN replaces these with a lightweight digital bus system, reducing train weight and improving fuel/energy efficiency.