Melbourne’s major train stations have moved to escalators and lifts as the way to and from platforms. While there are some rules for use posted on them, keeping to the left if not moving isn’t one of them.
Despite the short set of instructions its common enough to find hand carts on the escalators transporting loads too heavy to carry. This was common for deliveries to the kiosks when they were operating at Flinders St Station:
The move away from the ramps which historically provided access to the platforms did remove some examples of now inadequately safe designs and created more floor space on the platforms, but it leaves a subset of passengers with the lift as the only option. Given the demand for the lifts and their longer wait times, people will just squeeze onto the escalator even if that blocks other passengers.
This illustrates the inefficiency of escalators extremely well, many users will not (or can not) walk forwards to fill up gaps. These gaps also form just by the queue of passengers getting onto the escalator , some passengers will have a preference for the left or right hand side. Convention around the world is for stationary riders to keep to the side which that county drives on allowing “overtaking” by people walking up the escalator. But if two passengers arrive alongside each other at the entry of the escalator with the same left/right preference they will leave the other side empty as they board, as the treads continue moving forward the gap appears.
The seconds saved by walking along the escalators can be quickly nullified by any time spent waiting in a queue to enter it. A real world test of escalator efficiency found that it would be better overall for people to not try and take different sides but rather just get on the escalator as quickly as possible during congested periods. By instead encouraging fast filling, a minority will lose a few seconds and the majority will gain many more in return.
Certain bulky loads can enter the escalator without forming a gap, and bicycles are notably absent from the list of exclusions on the escalators. Some bicycles are narrow enough to still allow people to pass by.
But in that example the bicycle extends forward and backward taking up the space of several people, extending the queue behind.
The dual lane notion of escalators has introduced implicit social pressures that aren’t formally expressed or matched on the almost identical stairs, or similar ramps. Within the restricted width passengers are typically careful to keep hard against the sides of the escalator, but on stairs or ramps they will spread out significantly more. Escalators carry more people through a given space not because they are moving faster than walking (they are actually slower) but because people are accepting being crushed into a denser crowd. Its more noticeable in lifts when people will generally accept squeezing up to make room for another passenger. knowing how they would prefer others to accomodate them in the same situation.
But how to convince people that they should simply get on the escalator as quickly as possible? There are no formal rules in place either way, but the social expectation is to accede to the selfish in detriment of the whole.