While the solution by Thaddeus Jones will work, do yourself a favour: Don;t store data in VARCHAR or NVARCHAR columns unless it is genuinely a string. Store data in appropriate datatypes: integers in INT columns, floating point numbers in FLOAT columns, date in DATE, DATETIME, or DATETIME2. It saves a lot of problems later and makes your code much, much, easier when you want to work with the data, because the column can't contain invalid data. If you have an integer TrainNumber column, then nothing can put "Jaipur" or "12K" in there, causing your code to fail because it isn't a number.
Then all you have to do is
int rowValue = (int) row["TrainNo"];
And off you go...