public void TestTrainNumberCheckSum()
 {
     Assert.AreEqual(4, ChecksumCalculator.TrainNumberCheckSum("50852673106"));
     Assert.AreEqual(1, ChecksumCalculator.TrainNumberCheckSum("50853633111"));
     Assert.AreEqual(0, ChecksumCalculator.TrainNumberCheckSum("50858633111"));
     Assert.AreEqual(8, ChecksumCalculator.TrainNumberCheckSum("91854450008"));
     Assert.AreEqual(4, ChecksumCalculator.TrainNumberCheckSum("50652673306"));
 }