Investors interested in Transportation stocks should always be looking to find the best-performing companies in the group. GasLog Partners LP (GLOP) is a stock that can certainly grab the attention of many investors, but do its recent returns compare favorably to the sector as a whole? By taking a look at the stock's year-to-date performance in comparison to its Transportation peers, we might be able to answer that question.GasLog Partners LP is one of 142 companies in the Transportation group. The Transportation group currently sits at #2 within the Zacks Sector Rank. The Zacks Sector Rank includes 16 different groups and is listed in order from best to worst in terms of the average Zacks Rank of the individual companies within each of these sectors.The Zacks Rank is a proven system that emphasizes earnings estimates and estimate revisions, highlighting a variety of stocks that are displaying the right characteristics to beat the market over the next one to three months. GasLog Partners LP is currently sporting a Zacks Rank of #2 (Buy).The Zacks Consensus Estimate for GLOP's full-year earnings has moved 8.7% higher within the past quarter. This means that analyst sentiment is stronger and the stock's earnings outlook is improving.Based on the latest available data, GLOP has gained about 17.8% so far this year. In comparison, Transportation companies have returned an average of -23%. As we can see, GasLog Partners LP is performing better than its sector in the calendar year.Another Transportation stock, which has outperformed the sector so far this year, is Marten Transport, Ltd. (MRTN). The stock has returned 13% year-to-date.The consensus estimate for Marten Transport, Ltd.'s current year EPS has increased 9.3% over the past three months. The stock currently has a Zacks Rank #2 (Buy).Breaking things down more, GasLog Partners LP is a member of the Transportation - Shipping industry, which includes 46 individual companies and currently sits at #51 in the Zacks Industry Rank. On average, this group has gained an average of 19.5% so far this year, meaning that GLOP is slightly underperforming its industry in terms of year-to-date returns.On the other hand, Marten Transport, Ltd. belongs to the Transportation - Truck industry. This 12-stock industry is currently ranked #13. The industry has moved -26.5% year to date.Investors interested in the Transportation sector may want to keep a close eye on GasLog Partners LP and Marten Transport, Ltd. as they attempt to continue their solid performance. 5 Stocks Set to Double Each was handpicked by a Zacks expert as the #1 favorite stock to gain +100% or more in 2021. Previous recommendations have soared +143.0%, +175.9%, +498.3% and +673.0%. Most of the stocks in this report are flying under Wall Street radar, which provides a great opportunity to get in on the ground floor.Today, See These 5 Potential Home Runs >>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 GasLog Partners LP (GLOP): Free Stock Analysis Report Marten Transport, Ltd. (MRTN): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research