After reaching an important support level, Greenbrier Companies (GBX Quick QuoteGBX - Free Report) could be a good stock pick from a technical perspective. GBX surpassed resistance at the 20-day moving average, suggesting a short-term bullish trend.

The 20-day simple moving average is a popular trading tool. It provides a look back at a stock's price over a 20-day period, and is beneficial to short-term traders since it smooths out price fluctuations and provides more trend reversal signals than longer-term moving averages.

Like other SMAs, if a stock's price is moving above the 20-day, the trend is considered positive. When the price falls below the moving average, it can signal a downward trend.

Shares of GBX have been moving higher over the past four weeks, up 6.9%. Plus, the company is currently a Zacks Rank #3 (Hold) stock, suggesting that GBX could be poised for a continued surge.

Once investors consider GBX's positive earnings estimate revisions, the bullish case only solidifies. No earnings estimate has been lowered in the past two months, compared to 1 raised estimates, for the current fiscal year, and the consensus estimate has increased as well.

Investors should think about putting GBX on their watchlist given the ultra-important technical indicator and positive move in earnings estimate revisions.