In an earlier conversation with hiro, he mentioned something that had me recollect an important experience from my old Army days ... and then that thought kind of ran away with its branching implications.
I'll go the long way:
These past 20 years, military doctrine and hardware in the West have been very narrowly focused towards GWOT and its particular requirements. Even in the first decade after the Wall fell, our main focus was on conflicts like the Yugoslav civil wars, which also were rather different from the kind of conflicts we'd been building our armies for.
Add to that the whole "End of Civilisation" and "Peace Dividend" political fantasy that was all too happy to keep a large portion of the development of heavier military hardware like tanks down essentially to minor upgrades of 80's technology.
It is only very recently that we've again started thinking about what major confrontations between standing armies might look like, and what the deeper implications of this are.
But that battlefield — that clash of standing armies — was the reality that we were building and preparing for during the Cold War. Consequently, it is also the reality of what all the build-up during the game's fictional 90's, until the break of hostilities in 1997, is geared for.
And ergo, the result of that development is also the environment and hardware that the characters will find themselves in the middle of.
In some scenarios, this might also be the precise kind of active shooting war the characters find themselves in the middle of.
So, what is it? When the fringes of an armoured division meet a mechanised division over the plains south of Linköping ... how does that battlefield differ from the GWOT battlefield in Kandahar, and a thousand other cities, towns, and valleys?
I need others to chime in with details on the GWOT battlefield — I never trained for it; my active stint in the Army ended literally weeks before the Wall fell — but the Cold War European battlefield was to a large portion all about armour.
This means battlefields where typical engagement ranges are measured in kilometres. FIBUA and CQB are an exception, not a rule.
An armoured battalion acts as a cohesive combined arms unity, with platoons of tanks and IFV's/APC's supporting one another; the mechanised infantry's chief role being to secure woods and other terrain where tanks are at a disadvantage, guarding the flanks; but the tanks constitute the main striking force, providing the core of firepower and mobility.
Consequently, the infantrymen aren't equipped with short-range weapons like carbines and shotguns; they have full-size assault rifles [discounting the M231, if applicable], GPMG's, and other support weapons, capable of engaging enemies at ranges of hundreds of metres.
You have anti-tank helicopters and attack helicopters, you have air support, and you have artillery. You have anti-air artillery and missiles to keep the enemy's helicopters and air support at bay. You have combat engineers.
But it all revolves around supporting the armoured unit's operations — hence, the platforms are self-propelled, in order to be able to keep up with the tanks' mobility.
It's a whole different kind of war than many of those who were in the military in the 90's and onwards trained for.
And this gets me thinking about the battlefield environment.
So, distances tend to be extended; vehicles tend to be heavy, tracked affairs — light vehicles and wheeled armoured vehicles operate as scouts or in other roles where mobility provides more critical protection than armour. In the game's altered 90's, we should have a true 24hr battlefield, with sensor systems able to ensure mobility as well as acquire and engage targets at range at dead of night, in vehicles as well as in the hands of dismounted troops. The battlefield has both depth and fluidity; there won't be a static line where units shoot at one another from either side; tanks on the offensive will use their mobility to manoeuvre through enemy positions, on the defensive, they'll be dug down in prepared positions, but ready to move and regroup in an instant.
Then there's the noise.
Anyone who has stood anywhere near — as in, within several tens of metres of — a tank firing live ammo from its main gun, especially sabot rounds, can attest that it ... kind of rivets your attention. Even with ear protection, the noise is deafening; the shock wave is massive. At night, the muzzle flash seems to light up the whole landscape.
Another fun little fact to consider while on the topic — when a tank fires a sabot round (APFSDS; the standard antitank projectile), the sabot itself at this point in history is a metal chunk in three or four parts, that peels off the projectile immediately upon leaving the barrel ... travelling at nearly 2km/s; much faster than a rifle bullet. The sabot petals are each perfectly capable of dealing severe damage to unprotected troops or hardware hundreds of metres away from the firing tank. Not something that you'd bother with most of the time, but an opportunity for you as a GM to inject a little unexpected complication into a situation, now and then.
Back to the subject of noise; in indoor spaces, even small arms fire is uncomfortably loud — and rounds fired from short barrels make a lot more noise than the same rounds fired from a long barrel.
So ... why this long story?
I think it might make a good picture to have at the back of one's mind when GM'ing the environment, is all.
Depending on the circumstances in your campaign, the tanks may still be running ... or they may all have run out of fuel. But in some sense or other, they'll still be there, if in no other way than that the military context surrounding the setting and the characters was built around the assumption of them being there.
Hope it comes in useful — but in the meanwhile, feel free to fill in more if you've got something!