The Q2 earnings season is in its nascent stage with 30 S&P 500 participants having reported results so far according to the latest Earnings Preview. In fact, the season started with big names in the banking space like JPMorgan Chase & Co. JPM and Citigroup C.This week will see 214 companies, including 68 S&P 500 participants, revealing their Q2 results.The above report projects S&P 500 companies’ bottom-line growth of 6.6% year over year. Additionally, stocks in the highly sought-after fraternity are projected to end Q2 with their top line expanding 4.5%. In fact, 11 of the 16 Zacks sectors are expected to see their bottom line expand on a year-over-year basis at the end of the quarter.One such sector is the highly diversified transportation sector. In fact, the participants from this space are likely to end Q2 with the top and the bottom line expanding 4.7% and 9.1%, respectively. Notably, both the figures compared favorably to the readings in Q1, when earnings contracted 17.8% and revenues grew 6.9%.Moreover, the sector has already seen contrasting Q2 reports from two key players, Delta Air Lines DAL and United Continental Holdings UAL. While Delta posted lower-than-expected earnings and revenues, United Continental topped on both the fronts.Given this backdrop, investors interested in the transportation space will keenly await Q2 reports from key sector participants like Union Pacific Corporation UNP, GATX Corporation GATX and Marten Transport, Ltd. MRTN on Jul 20.According to our quantitative model, a company needs the right combination of two key ingredients – a positive Earnings ESP and a Zacks Rank #3 (Hold) or better – to increase the odds of an earnings surprise. You can uncover the best stocks to buy or sell before they’re reported with our Earnings ESP Filter.Based in Omaha, NE, Union Pacific Corporation is a renowned U.S. Class 1 railroad company. We expect the company to report better-than-expected earnings per share in Q2 on the back of lower costs. This is because it has an Earnings ESP of +1.46% as the Most Accurate estimate is at $1.39, while the Zacks Consensus Estimate is pegged at $1.37. Also, it currently carries a Zacks Rank #2 (Buy) (read more: Union Pacific Q2 Earnings: Another Beat in Store?).Union Pacific Corporation Price and EPS Surprise Union Pacific Corporation Price and EPS Surprise | Union Pacific Corporation QuoteThe next company is GATX Corporation, based in Chicago, IL. It leases, operates and manages widely used assets in rail, marine and industrial equipment markets. The chances of this company beating the Zacks Consensus Estimate in this quarter are less, despite its Zacks Rank #3. This is because it has an Earnings ESP of -4.55% as both the Most Accurate estimate is at $1.05, while the Zacks Consensus Estimate is pegged at $1.10. You can see the complete list of today’s Zacks #1 Rank (Strong Buy) stocks here.GATX Corporation Price and EPS Surprise GATX Corporation Price and EPS Surprise | GATX Corporation QuoteLastly, Marten Transport, Ltd., based in Mondovi, WI, is a long-haul truckload carrier. Our model does not indicate that the company is likely to beat earnings in Q2. This is because the company has a Zacks Rank #3 but an Earnings ESP of 0.00% (as both the Most Accurate Estimate and the Zacks Consensus Estimate are pegged at 15 cents).Marten Transport, Ltd. Price and EPS Surprise Marten Transport, Ltd. Price and EPS Surprise | Marten Transport, Ltd. Quote5 Trades Could Profit "Big-League" from Trump PoliciesIf the stocks above spark your interest, wait until you look into companies primed to make substantial gains from Washington's changing course.Today Zacks reveals 5 tickers that could benefit from new trends like streamlined drug approvals, tariffs, lower taxes, higher interest rates, and spending surges in defense and infrastructure. See these buy recommendations now >>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Delta Air Lines, Inc. (DAL): Free Stock Analysis Report United Continental Holdings, Inc. (UAL): Free Stock Analysis Report GATX Corporation (GATX): Free Stock Analysis Report Union Pacific Corporation (UNP): Free Stock Analysis Report Marten Transport, Ltd. (MRTN): Free Stock Analysis Report J P Morgan Chase & Co (JPM): Free Stock Analysis Report Citigroup Inc. (C): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research