My recent post on a woeful tip I not-so-advertently bestowed on a hard-working Grand Central beer man elicited a comment from a reader calling me a cheap-ass for not tipping a buck.

Granted, I’m considering the source — said commenter is an angry Rhode Islander who’s happiest when he’s stirring things up. But he raises a valid question: What’s a fair tip for a Grand Central beer man (and when I say “beer man,” I’m including that one woman who operates a Grand Central beer cart too).

Of course, the pay scale of Grand Central commuters ranges from the Greenwich hedge fun billionaire to schoolteachers and reporters who can barely make their mortgage. But what’s a fair middle ground?

I tend to tip a quarter or two. Here’s how I see it: If I’m buying a $2 beer at a deli outside Grand Central, I’m not tipping a penny. If I’m buying a beer from one of those bakeries or pizza stands inside Grand Central, I’m not tipping a penny.

If I’m buying a $7 pint at Annie Moore’s, I’m tipping a buck.

So if I’m buying a $2.25 Sam Adams in Grand Central, the tip should be somewhere in the middle, like 25 - 50 cents. The guy is doing the same thing as the worker at the bakery or pizza stand across the Grand Central concourse, but since it’s a lone owner-operator, I’m inclined to throw him a little something.

I have no idea how well off the beer guys are, but judging by some of their haircuts, they’re not wallpapering their bathrooms with Benjamins. If any beer guys (or gal) read this, I’d love to hear from you about fair tips.

How much do you, fellow rider, tip?

Almost forgot about this from a few Fridays ago. As the weekend officially begins, a young Asian woman is buying a cocktail on the Grand Central platform around 5:30. The beer man’s got dirty blond hair in a bowl cut. Apparently the girl is a quarter or so short on the cocktail’s fee; she’s about to rummage through her purse to make up the difference.

But the beer man’s not having it.

“You gotta pay your rent, right?” he says cheerily, telling her to save her change.

She smiles and nods.

“You’re not smoking pot, right?” he adds.

Again, she smiles and nods.

He then raps a knuckle on the makeshift bar, the way a bartender does to signify a free drink is coming your way.

It wasn’t the brightest of banter, but it had some heart.

The beer guy posted next to Track 112 in Grand Central.

It had been a taxing day, shall we say, at work. I waited for the 6 train at 28th to grab the 5:46, get home, and relax while playing cars with Little G.

I waited. I waited. I waited some more. The garbled message came on the loudspeaker: there was an uptown 6 train approaching 14th Street.

I was going to miss the 5:46, and had to endure the inexcusable 24 minute wait (what is this, Topeka?) for the 6:10. The 6 train took 13 minutes to arrive.

I got to Grand Central and decided a beer might help my frame of mind. I approached you, doughy beer man in pale blue shirt and pale white complexion, my eye on a Bud tall boy.

I thought I could pay in silver, unload some of that change that had been clanking around in my pocket all day. It took a moment. You helped the guy behind me. That was cool.

I came up with $1.80, 20 cents short. I paid with a five and you gave me change. The whole exchange took about a minute.

I thanked you and, as I started to walk away, you looked away and mumbled something. I slipped into default mode, smiling and nodding.

A few seconds later, it dawned on me what you said:

“You just cost me like five customers.”

Mr. Beer Man, I’m sure you have rough days too: People who pay with $20s, people who complain when you run out of Mike’s Hard Lemonade, people who yell at you for charging $4.50 for bland American claret.

What, Mr. Beer Man, did you seek to gain by informing me that I’d just cost you “like five customers?”

I’ll be taking my Bud money elsewhere, dear Beer Man.

Sincerely,

Trainjotting

Your guest editor is of a geekier bent than your regular virtual conductor, so here’s my favorite train-related tech tip. Did you know that the MTA’s Web site contains its own version of the Big Board — the Grand Central Terminal departure info displayed on monitors around the station?

Of course you didn’t. That’s because the MTA’s Web site is designed as if its main aim is to hide information about the workings of our transit system from from al Qaeda.

It’s there though. Even better, it updates on its own in real time! Here’s the link:

http://as0.mta.info/mnr/html/bigboard.cfm

OK so that’s all well and good - but here’s the real tip. Take this post and email it to your favorite mobile device. Then click on the link above. If your handheld is cool enough (I know this works on a Treo at least, I don’t see why it shouldn’t work on a Blackberry as well) you’ll have your own personal Big Board that you can consult for track info as you approach the station. (Be sure to bookmark it for future reference.)

With this weapon in your commuting arsenal you’ll no longer need to weave through the the clot of amateurs staring blankly at the monitors as you bust through the terminal doors at 6:17:3o trying to make the 6:18. Instead you can run straight to the beer guy and hope there isn’t a line.