I love to kick off the new trading week by taking a quick peek at companies that have just hiked their dividends. It's not just about the money. A company that is easing up on its pocketbook probably has improving fundamentals to back up that generosity.

Readers of the Income Investor newsletter can certainly appreciate that kind of thinking. Let's take a closer look at four of the companies that inched their payouts higher over the past week.

We'll start with Norfolk Southern (NYSE: NSC). The railroad operator choo-choo-chewed its way up, boosting its quarterly dividend by 12% to $0.29 a share. Norfolk also increased its payout rate just six months ago.

There may be more to the sleepy trainsmiths than just puffs of steamy smoke. With Berkshire Hathaway's (NYSE: BRK-A) (NYSE: BRK-B) Warren Buffett singing "I've been working on the railroad" as he grows his stake in Burlington Northern (NYSE: BNI), and Norfolk handing out more pocket change, all signs point to compelling plays in the transportation sector.

Then we have Polaris (NYSE: PII) revving up. The maker of all-terrain vehicles, snowmobiles, and motorcycles propped up its quarterly disbursement by 12%, to $0.38 a share. The move shouldn't surprise its smiling shareholders. Polaris has bumped up its yield in each of the past 13 years.

Fastenal (Nasdaq: FAST) is another hiker. The chain of more than 2,000 industrial and construction supply stores is growing its semi-annual dividend. Investors will now receive $0.25 a share every six months, topping last year's $0.23 a share. Why not? The company just capped off a year in which sales and earnings climbed 14% and 17%, respectively. The wiggle room is certainly there to justify the kinder distributions.

Finally, we have Comerica (NYSE: CMA) to bank on. Yes, there are still financial-services companies coming through with payout increases. Comerica's quarterly dividend is climbing 3% higher to $0.66 a share. Investors may be feeling skittish about the sector, but that leaves Comerica's stock yielding an impressive 6.6%. These are trying times, but keep in mind that Comerica has now boosted its dividend rate for 39 consecutive years.

Subscribers to the Income Investor newsletter love when companies send more and more money to their investors. Want to see what is being recommended these days? Go ahead and give the newsletter service a shot with a 30-day trial subscription. Who knows? Maybe the next thing to get hiked will be your interest.

Longtime Fool contributor Rick Munarriz pays attention to yield signs. He does not own shares in any of the companies in this story. Berkshire Hathaway (B Shares) is an Inside Value and Stock Advisor newsletter selection. The Motley Fool owns stock in Berkshire Hathaway (NYSE: BRK-B  ) . Rick is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early. The Fool has a disclosure policy.