long and short train

[PJW]

Certainly this is a different "take" on the question.

Goes to show what "workarounds" are sometimes necessary to overcome a difficulty that ideally should have been avoided if everything had been delivered to plan.

And yes it is often the Operators and also the Customers who pay the price when the engineers let them down!

In the Metro Line I work in, the company planed the 4car and 6car trains run together as there are not enough 4car trains for opening. The background is that 6car trains were all rent from other companies, we want to use our train--4car train when the extension line was opening. We did a summary of the shortcomings of this senario.

1\ Platform Screen Door is too difficult to operate seperately for these two kinds of trains. So PSD only open for 4car trains. When 6car trains arrived, only 4car PSD open. It also requires operating staff to cut the 6car train into 2 parts, and passengers are not allowed to entry the last 2 cars. What is more worse is changing cab. When the train is changing cab, it needs staff to close other 2 cars in the other end.
2\The stopping point is also a problem. You can imagin this issue. It always brings difficulties to the operator.
3\ When the actual headway is not too short, more than the design limit, the length of train does not affect too much. But when the headway is very close to the limit, I think it may cause problems.
4\It requires passegener information system is good enough. It needs to remind passengers to stand in proper position for the next train. If the next train is 4car while he stand in the position which is just the end of 6car train, he has to run for nearly 40meters to get on the train.

In summary, I find I state the issue mostly from the view of the operating staff, not the siganlling engineer.^_^