Not apparently.
One of the "features' of the ATC/ATO is completely unattended operation of equipment within the yard limits. This means that trains can be remarshalled, sent for cleaning and servicing, and prepped for entry into service or stored after it without having anyone trackside or onboard.
That the system allowed an accident in this configuration is extremely problematic, as it is set up the same as the mainline signal system and supposed to offer the same safeguards as it - but because it operates at low speeds and without passengers is deemed to be "safe enough" in its current configuration to operate unattended (versus on the mainline, were there would need to be additional measures to protect the trains from the public and vice versa).
If it happened in the yard, it can happen elsewhere in the system. For something as safety-critical as the signal system, that is unacceptable. Which is why it's been closed since Thursday - they need to inspect every single potential route capable within the system and ensure that there are no other "blind spots" that would allow this to happen again. And that's why I'm skeptical that testing will resume quickly.
Dan