When concrete railway crossties are installed in North American freight track and subjected to flexural loads, center negative bending is one of the most critical demands. However, the ultimate flexural capacity at the crosstie center is often unknown and hard to obtain. Because railroads do not always know what the remaining flexural capacity of concrete crossties is, it becomes difficult to assess whether crossties should be removed from service or if it is safe to increase axle loads as an example. To address this challenge, we present a predictive mathematical model based on laboratory experimentation data of various common pretensioned concrete crosstie designs to estimate their center negative bending strength. The model is developed using least absolute shrinkage and selection operator (LASSO) techniques. The final derived equation uses predictor variables that are easily interpreted and applied, and the results are adequate for approximations when limited information is available about the crossties’ characteristics and lengthy structural calculations or additional laboratory testing is not practical. For the investigated crosstie designs, the maximum prediction error was 5.5%.