Meditating on Public Transport

I practice Samatha meditation when I am traveling on the plane. If shot distance travel it is better to practice Vipassana otherwise you might miss the place to get off from the bus. Buddhists are expected to practice mindfulness throughout the day.

I felt these posts dealt with being mindful on public transport rather than meditation

I don't feel like there is necessarily a distinction between being mindful and meditating. In my experience, the goal of meditation is to get insight, and the way to practice meditation is to be mindful of what happen in the present moment in the frames of reference, which are the body, the mind, feelings and dharmas.

That being said, the context and the environnement surrounding you matters a lot, and you can take advantage of that. There will not be the same kind of activity in your mind if you are on a public transport rather than in your room. There is stuff to be aware of that can happen only when you are on public transport, so don't miss your chance to get insights by being distracted !

The whole purpose of formal meditation in a quiet place is to train yourself to be able to meditate anywhere throughout your day, you have to do it otherwise you will not make any progress. As the musician knows that doing his scales everyday is necessary to make music but is not music itself, we should know that formal meditation is only a mean to an end. So to answer your questions :

Is meditation itself possible/recommended on public transport?

Yes ! Go for it any way you like.

Would the quality of such meditation, if lesser, diminish the quality of general meditative practice?

If you feel weird while doing it fearing what people might think of you, or unable to calm down your mind, great ! Finding out ways to relax in the present moment in these difficult conditions will enhance your ability to meditate in any situations.

Meditation is a skill that develops over time. Don't worry about the quality of your meditation. You might not feel like this is going anywhere when you meditate in awful conditions, but keep at it and you will be rewarded !

Meditating on Public Transport

Is meditation itself possible/recommended on public transport?

Proper practice revolves around an integration of mindfulness meditation into daily life. Sitting (cushion) meditation practice is meant to develop mindfulness to such a degree that it can be transferred into daily life and ultimately into constant mindfulness until one can ultimately become free from Samsara. Walking meditation is another great way of bridging ones practice into daily life.

Meditation in gradually noisier environments will be challenging but that's the idea. If one only practices at home but can't use the practice outside of ones sitting practice, then it's not beneficial.

It's beneficial to meditate everywhere and all the time.

As an example; when I have patient consultation, I'm mindful of my abdomen rising and falling with each breath, the feeling of my lips moving when talking, the sound of my own voice, the seeing that goes on when seeing a patient, the feeling of pressure from sitting on a chair, the sound of birds chirping outside etc. One object at a time.

Even though it might be difficult to practice in public transport it should be done and with time it will become effortless. Don't worry about the quality it will become refined with practice. It's like learning to shoot a bow. With time and consistent practice one will finetune the movements, reduce energy consumption and eventually be able to do it effortlessly. It's the same with meditation practice in noisy environments.

At some point the mind will begin to incline towards being mindful due to the purity and simplicity of being in the present moment. When that happens there will be a strong momentum driving the mind towards mindfulness and away from unmindfulness. At that point it begins to become effortless. One does not have to apply and direct (vitakka and vichara) the mind anymore.

Would the quality of such meditation, if lesser, diminish the quality of general meditative practice?

No, never. It will build, develop, cultivate and add to "general meditation practice".

A doctor who specializes in a field will be good but a doctor who specializes in several fields will be even better.

A fighter who specializes in one school of martial arts will be good. A fighter who specializes in several schools of martial arts will be even better.