It is obvious to me that neither DJF or Transtopic have used Central or Town Hall in peak hour. Anybody who has knows what I'm talking about when waiting for your train on a completely packed platform 1,2 or 3 only to see that it is full already as it arrives and you can't even get on the train because it is so full. People still try to get on and they are hanging out the door and there is a whole thing where they try to push in but can't fit in.The crucial point you continually overlook sims, is that the new CBD rail line will add another 3 stations in the CBD core, Central Metro, Pitt St and Martin Place, and it will spread the interchange load, reducing platform congestion at the existing stations. It wouldn't matter whether the new line is metro or ST. It's irrelevant making comparisons with existing conditions. For example, Bankstown metro commuters heading for North Shore and Macquarie Park destinations will have a direct run and will no longer have to interchange and Eastern Suburbs commuters with similar destinations will be able to interchange at Martin Place instead of Town Hall.
The guard can't close the doors because he is completely reliant on the trains cameras if it has them to see when it is safe to close the doors and the station attendant is overwhelmed by all the people on the platform. The guard can barely see 2 carriages ahead because of this crowding and the train continues to sit for several minutes. So now the train is late and so is every single one behind it which may already be waiting in the tunnel behind this stationary train. Finally after maybe even 4 minutes at the platform the guard manages to get the doors shut unless some idiot tries to hop on at the last moment delaying the train even longer.
DJF talking in channels is clear that he is talking only in theory because anybody who knows and uses Town Hall and Central knows that theory is just bulldust. Even if you have the same stopping patterns there will still be different destinations meaning you will still have people waiting on the platform for their train.
There is also a need to take in to consideration the cumberland line and it's 4 trains an hour and how it fits in to all these extra services.
The proposed ATP/ATO upgrade won't come into effect until the new CBD metro line is operating and perhaps I mistakenly assumed that you were aware of this. I agree with you to a point that the signalling upgrade alone won't allow for higher frequencies on the lines as they currently exist, but that won't be the case after the new line opens. The other significant factor is that the signalling upgrade will allow for the introduction of moving block signalling in place of the outdated fixed block. This will allow trains to safely travel at higher speeds with closer headways.
It's going to allow for 24tph to operate on all of the existing lines through the CBD with DD trains or the government wouldn't be wasting its money. Just accept it's underway. It's already been confirmed that T4 on the ESR will increase by 30% from 18tph to 24tph (it's actually a 33% increase).